Dataset Viewer
Auto-converted to Parquet
url
stringlengths
38
133
thread_title
stringlengths
8
109
posts
listlengths
1
495
scraped_at
stringdate
2025-10-17 16:13:05
2025-10-19 01:29:01
post_count
int64
1
495
domain
stringclasses
1 value
subdomain
stringclasses
6 values
has_op_post
bool
2 classes
https://www.eevblog.com/forum/beginners/!help!-altuim-designer-pcb-layout/
!HELP! Altuim Designer PCB Layout - Page 1
[ { "post_id": "", "author": "YaSaRa_N", "author_rank": "Contributor", "is_op": true, "timestamp": "July 17, 2019, 04:12:23 am", "content": "Hi!I am designing a Micro-mouse robot as a hobby project. I did the schematic using the EasyEDA online editor. that is because i can directly chose parts from LCSC.(I use LCSC because of the lowest shipping rates). however, after creating the schismatic using EasyEDA, I convert it to a PCB and then exported it as a Altium PCB ducument(.pcbdoc) to do the routing.Once I opened the file from Altium it works fine except for that there is a white box around each component. (as shown in the attached image. it only appears once i selected the component)it seems to be a clearance thing. as in the image 1 , I cannot move R48 or R50 closer to the SW5. when the components are in either horizontaly or verticly, this white box is basically the package outline and its ok.but when i rotate a component, it becomes bigger. How can i get rid of this ? i am using AD19.Thank uou." }, { "post_id": "", "author": "YaSaRa_N", "author_rank": "Contributor", "is_op": true, "timestamp": "July 17, 2019, 06:02:24 am", "content": "Quote from: blueskull on July 17, 2019, 04:14:43 amI disabled the component clearance rule but no luck.At the very beginning of the layout i was able to place the components such that the white box overlaps. but now i cannot.So it must be a setting that i changed ?" }, { "post_id": "", "author": "YaSaRa_N", "author_rank": "Contributor", "is_op": true, "timestamp": "July 17, 2019, 04:11:18 pm", "content": "Quote from: blueskull on July 17, 2019, 06:10:25 amI tried that. no luck.however I installed AD18 and it seems to be working fine. I think it might be a bug in AD19. anyway problem solved. Thanks for the replies.now i can place components anywhere i want. even on top of another" }, { "post_id": "", "author": "Dave", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 18, 2019, 04:56:23 am", "content": "If you want clearance rules to work correctly in Altium, you need to have 3D models embedded in the footprints. Otherwise it does what you've noticed: draw stupid rectangles around the footprint and claims everything is colliding. This often isn't a problem if all components are horizontal or vertical, but it's absolutely useless at any other rotation angle." } ]
2025-10-17T18:06:44.387219
4
electronics
beginners
true
https://www.eevblog.com/forum/beginners/!updated!-beginners-shopping-list!/
!UPDATED! Beginners Shopping list! - Page 1
[ { "post_id": "", "author": "Lisbeth", "author_rank": "Contributor", "is_op": true, "timestamp": "May 11, 2015, 01:45:04 am", "content": "Hey everyone!Bout a couple weeks ago, I made a post here about my shopping list. I realized I wasn't getting as much bang for my buckby a nice friend of mine as he suggested I try SparkFun. I check it out, and dear lord in heaven, I get SO much more!First off, the soldering Iron. Geniuine Hakko, which is always a good sign. I also found the ever so elegant Chisel tip so that'staken care of as well. But I also found some alligator clip jumpers, a moderately good digital multimeter, a screwdriver kit with a large bit set,spools of differently colored hookup wire (solid core), a nice tool kit that comes with a bundle of tools and with a nice carrying case. ^^All in all for slightly under 200$! I also went and added a notebook and hackerspace passport, cuz why not? X3Here's the wishlist containing all the tools if you wanna check them out!https://www.sparkfun.com/wish_lists/111182I would love some more suggestions and tips! ^^" }, { "post_id": "", "author": "GreyWoolfe", "author_rank": "Unknown", "is_op": false, "timestamp": "May 11, 2015, 02:07:54 am", "content": "Better price for the Hakko here:http://www.all-spec.com/products/FX-888D.html?gclid=CjwKEAjwg7yqBRCu5NmlgMm6i08SJADDEudZ9Sf0YXucTKmGDJhhiXPX2ohhyQXCAk3Sv1rzSiYATxoCRvfw_wcBPlease don't try to measure anything but low voltage with that meter, it's too dangerous. I have 'precision' screwdrivers with bit sets and I like them but I also have numerous screwdrivers in different sizes/styles. You will find trying to fit the bit sets into tight spaces becomes difficult with the bulge on the shaft that holds the bits. It seems that the more individual screwdrivers I get, the less I use the sets. You might be better suited by buying screwdriver sets instead. It will cost more but hey, who doesn't want to have more toolsDon't forget solder/flux, isopropyl alcohol, flush cutters, dental probes, locking hemostats (probes and hemostats are plentiful and cheap at flea markets). A package of bamboo skewers also serves double duty as non conductive high tech pointy thingies for probing circuits and old toothbrushes are good for cleaning flux residue. A variable output power supply will also be useful. I'm sure others will add to this." }, { "post_id": "", "author": "Lisbeth", "author_rank": "Contributor", "is_op": true, "timestamp": "May 11, 2015, 02:33:13 am", "content": "Quote from: GreyWoolfe on May 11, 2015, 02:07:54 amWhy do I have to have such a small budget..." }, { "post_id": "", "author": "xrunner", "author_rank": "Super Contributor", "is_op": false, "timestamp": "May 11, 2015, 02:40:42 am", "content": "Quote from: Lisbeth on May 11, 2015, 01:45:04 amHow much more money canweyou spend?" }, { "post_id": "", "author": "cellularmitosis", "author_rank": "Unknown", "is_op": false, "timestamp": "May 11, 2015, 03:33:25 am", "content": "If you've got another $50, you should get a power supply.I've been happy with this one:http://www.ebay.com/itm/Bench-Power-Supply-0-2Amp-0-18VDC-Adjustable-DC-Regulated-CSI1802X-/221584095605?pt=LH_DefaultDomain_0&hash=item339770f975I'd suggest replacing the pots with 10-turn pots as your first hack on this piece of equipment.https://www.eevblog.com/forum/testgear/picked-up-a-csi1802x-bench-supply-%28$50-0-18v-0-2a%29/A good goal would be to try to limit yourself to only buying one (crappy) power supply ever. When you inevitably need second one, or one with better specs, design and build yourself! Building your own power supply seems to be like a Jedi making his own light saber: at some point every EE hobbyist must do this as a right of passage" }, { "post_id": "", "author": "Johndi", "author_rank": "Contributor", "is_op": false, "timestamp": "May 11, 2015, 03:48:16 am", "content": "I noticed that your flag states you're in the US. If that is the case, then I would look at Lowes, Home Depot, or your local hardware store for a precision screwdriver set. I have the HDX 23 piece precision screwdriver set pictured here and its done me well for things that I've needed to do for the price:http://www.homedepot.com/p/HDX-Precision-Screwdriver-Set-23-Piece-009-177-HDX/203436713" }, { "post_id": "", "author": "Lisbeth", "author_rank": "Contributor", "is_op": true, "timestamp": "May 11, 2015, 05:33:32 am", "content": "Quote from: Johndi on May 11, 2015, 03:48:16 amThe one I have in mind has a bit more than the one you suggest:4\" ABS Plastic Handle with Rubberized Grip5\" Flexible Extension Neck5\" Steel Extension BarTorx T4, T5, T7, T6, T8, T10, T15, T20Hex Socket 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4Tri-Wing 1.5, 2.0Triangle 2.0, 2.3Star 1.5, 2.0Center Dot 1.0PZ0, PZ1M 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5H 2.3Slotted 1.3, 1.5, 2.0, 2.5, 3.0, 4.0Phillips PH00, PH0, PH1, PH2" }, { "post_id": "", "author": "Lisbeth", "author_rank": "Contributor", "is_op": true, "timestamp": "May 11, 2015, 05:38:22 am", "content": "Quote from: cellularmitosis on May 11, 2015, 03:33:25 amI'm thinking about building my own, nothing too powerful, then I can move on to buy my own." }, { "post_id": "", "author": "kizzap", "author_rank": "Unknown", "is_op": false, "timestamp": "May 11, 2015, 09:12:16 am", "content": "Quote from: Lisbeth on May 11, 2015, 05:33:32 amBeing that you are just starting out, I would consider getting something like this:I got that set at an \"ag\" show (agriculture:- farming) here in Australia for less then $5. I would be sure that you would be able to find something similar where ever you are.Then, get a decentish driver/handle, and it should get you through most problems you will face. The only exception to those are for those nasty screws that are recessed deep, in which case you generally need a better set of screwdrivers, but when that comes up, you can buy them then.As for designing the PSU: Great idea! Just don't do what I did, and let feature creep set in. Also be aware that any store bought one will be generally cheaper then building your own, as they have the benefit of mass production behind them." }, { "post_id": "", "author": "Lisbeth", "author_rank": "Contributor", "is_op": true, "timestamp": "May 11, 2015, 10:56:00 am", "content": "One issue I have been noticing with this post and the one before is that people keep linking me All Spec.Now don't get me wrong, All Spec is a great distributor for engineers. But I'm a hobbyist, and even thoughtheir soldering iron is cheaper than the one on SparkFun, the shipping does not... It adds 6 dollars and some changeto the original price. While buying the iron from SparkFun, or anything above 75$ on the site comes with free shipping.So yeah, I think I will buy from All Spec WAAAY down the road if I get really into it, but for now, I'm satisfied with whatSparkFun provides.Also, as far as the multimeter, I would not trust it as far as I could throw it. But, everybody has to start somewhere andI DO NOT intend to be messing with wall socket voltage any time soon. Also, it beats having to pay 40$ for a multimeterthat can do the same thing, except with better design. Sometimes you have to compromise..." }, { "post_id": "", "author": "nanofrog", "author_rank": "Super Contributor", "is_op": false, "timestamp": "May 11, 2015, 11:37:52 am", "content": "Quote from: Lisbeth on May 11, 2015, 01:45:04 amAs per theHakko FX-888D, you might want to consider getting it from TEquipment.net instead (comes with a free cutter).Free shipping over $99, which you'll reach just by adding a couple of tips. They even offer it in kits (extras are usually popular styles of tips).They also offer a discount (code sent via PM), which usually makes them extremely competitive on price, if not the cheapest source.Other Tools:Screwdrivers- I'd recommend considering a dedicated set or two for slotted, Phillips, and Torx (ideally, security Torx <has a hole drilled in the end of the screwdriver>, as they'll work on either security or standard Torx screws). TheWiha 26190(basic slotted & Phillips set; also includes a free pair of needle nose pliers), andWera 2067/6(Wiha doesn't offer a set of this type). Use a bit set elsewhere, and upgrade as needed.There is also something similar to bit sets, but it's an entire shaft length, instead of 1\" bits (aka System 4 blade products from Wiha;example). Pricing can be very similar or more than dedicated drivers, depending on the set (blade system is more expensive than 1\" bit versions, but do keep in mind, there's usually a screwdriver profile ground into each end, so 2x per blade; exceptions would be nut drivers).Cutters & Pliers- Freebies included with the recommendations above (Wiha set + Hakko FX-888D Kit 2).Tool Roll you linked; skip it due to ^. Other tools you'll want can be had inexpensively from eBay, such as thevacuum desolder pump, and a pair or two of tweezers (say afine point tip&curved tip, Vetus brand).DMM-UT139C. It has a nice set of features and has decent protection for the price (you'd be able to use it with AC/mains).Quote from: GreyWoolfe on May 11, 2015, 02:07:54 am+1Much better to get the commonly used drivers as individuals to avoid this problem. There are times even standard shaft lengths won't reach the bottom of some recessed holes (i.e. need 4\" shaft length).Quote from: GreyWoolfe on May 11, 2015, 02:07:54 am+1 here as well.Make sure the consumables mentioned ^ are quality brands, NOT stuff made in China (solder & flux) . Look for brands such as Kester, Multicore (Henkel), AIM (American Iron & Metals), Indium, MG Chemicals, and Alpha (Cookson). All-spec is a good source for these. Granted, you'll have to pay shipping, but they're very fair with it (little to no markup from what they pay), and in the end, they're still excellent pricing to your door (particularly useful regarding solder & flux for example).Solder(note the diameter, as it's good for general purpose; flux type is RA <= Rosin, Activated>, and a flux core size of 66, which is 3.3% by weight). Lead based alloys are easier to use (only lead issue is if you handle it, then stick your fingers in your mouth or up your nose without washing your hands first).FluxThis is also a quality RA product, and more importantly, is available in hobbyist friendly sized containers. You can dispense it with a needle bottle, refillable felt or brush tip pen, or just use a hobby artist brush (usually located inexpensively on eBay and similar sites; some may be counterfeits, such as BON-102 refillable brush pens, but should do the job)." }, { "post_id": "", "author": "Fat", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "May 11, 2015, 02:49:44 pm", "content": "I have had bad luck with the Vetus tweezers (maybe it was just my set?), the tips were very soft and after a few days they didn't touch at the tip. Tried rebending, but not much luck. I tried the Hakko brand, and have had some very good luck with them. They are not much more than a pair of Vetus if you shop around.I have a background in watch making (previous hobby) and am kind of particular about my tweezers.Fat" }, { "post_id": "", "author": "redshift", "author_rank": "Contributor", "is_op": false, "timestamp": "May 11, 2015, 04:36:15 pm", "content": "Here is my advice:Hakko FX-888D + Chisel Tip- This makes up more than half of your budget but if you're comfortable with that, it's a great iron. Ordering from TEquipment instead, as nanofrog suggested, makes a lot of sense. You'll also need some solder(the little tube in the roll-up kit doesn't count) and good solder is expensive.Sparkfun Multimeter- It's hard to give any advice on this unless you're willing to buy a more expensive meter. But no auto-ranging, doesn't power down on it's own, etc. Also, generally cheap meters like this have pretty awful continuity testers, but this is just a hunch.Six 25' Spools of 22AWG Wire- This seems like a good price especially considering you get six colours and a box that dispenses them.Aligator Clip Leads- Good price but I'd think if I had to choose between the two, I would opt for female-male and female-female test leads instead.Roll-up Tool Bag Kit- Convenient. But I think that you could source the components more cheaply. Also, the look of the solder, wire-strippers, cross-lock tweezers, and screwdriver set don't impress me.Screwdriver Set- Cool.But one thing I'm wondering about this list: Is this just theequipmentyou're buying? Because you have no parts to play with. Sparkfun will have competitive prices on genuine Arduino's, etc if you want to throw some stuff like that in too. Their components are expensive though.Lastly, do you have a breadboard? Some sort of power supply? Small collection of passives? Because you should get all of those things tooYou might be interested in getting something likethisorthisso that you don't have to worry about resistor/capacitor values for a while.Maybe we can have a follow-up digikey cart when you have some new projects in mind" } ]
2025-10-17T19:40:54.611368
13
electronics
beginners
true
https://www.eevblog.com/forum/beginners/$120-$150-budget-build-to-learn-soldering-need-opinions-on-my-selected-parts/
$120-$150 Budget build to learn Soldering. Need opinions on my selected parts - Page 1
[ { "post_id": "", "author": "OntoTheWoods", "author_rank": "Newbie", "is_op": true, "timestamp": "September 28, 2024, 05:57:49 pm", "content": "I would first like to preface this by saying that I do not live in the US, but rather in the Philippines. That's why some prices are cheaper, and some items like the Pinecil v2 are more expensive to procure.ModelProductPricePTS200 v2 AluminumSoldering Iron$21Aneng 683 TouchMultimeter$15Hayve 7\" HD 1200X 12MPDigital Microscope$39.5Yihua 8858-V (I don't think this is enough, more info below)Hot Air Station$19Yihua 948DQ-IFume Extractor$15Goot GS-104 MediumDesoldering Pump$14Anker Atom 2 60wIron Power Source0GRAND TOTAL123.5Soldering Iron - PTS200 v2 - $21I've searched reddit and found a couple commonly recommended Irons such as the:Pinecil v2 - $40.TS80P - $49HS02 - $31PTS200 v2 - $21 (just because the seller is doing a sale + coupons, original price is around $32)The Pinecil V2 and ts80p are one of the most commonly recommended budget Irons I've seen on that sub.However, I do think they're a bit outdated (but can be seen as a testament to their reliability) and based on the 2024 posts I've seen, the HS02 seems to be showing up quite a bit.But after digging deeper, I've seen the PTS200 v2 come up a few times, and just from a pure spec-wise comparison, The HS02 and PTS200 v2 seem to be the same in terms of build quality and having the ability to reach 100w.However, the similarities end there, the most glaring difference is their shape, and I find the PTS200's shape to be subjectively better. The PTS200 also use the ESP32, which theoretically could run IronOS, although official support for it is still currently unavailable. Although there's a custom firmware out for it, not that I know much about that, I just wanna plug my Iron and dissolve some solder. PTS200 can also accommodate t12,t13,ts tips.So there, that's how I decided on the PTS200 v2. I crossed out Pinecil/ts80p because they're twice the price, has less max power, and are less durable. I crossed out HS02 because if it's the same as the PTS200 in terms of build quality and 100w power, the next most important thing to consider would be the shape and then tip compatibility.Aneng 683 Touch - $15Any multimeter would've probably worked for my use-case. The design, recharge-ability, touch screen, manual mode (compared to the 681/682) and extra bells & whistles @ this price was just too attractive to pass up.Hayve 7\" HD 1200X 12MP - $39.5Seems like a decent plug-and-play solution at an attractive price.However, I'm a bit on the fence on this one as I have particular setup in mind wherein I could build a 4k streaming digital microscope. Would be a cool project to do once I get the hang of soldering.I could potentially can get a 4k Sony imx 678-based Microscope + Orange Pi + 4k capture card for around $110 and build my own 4k microscope set that can stream to my iPad Pro or 4k screen. Maybe add in another $15-20 for a built-in battery pack that I could read the power from as well and throw it to the feed for a truly wireless experience.Software-wise, it seems fairly easy to do in theory, but that's because I'm a programmer and already made much more complicated web apps. Just setup Nginx as your web server, install a video encoder, setup to encode the video sent by the capture card, encode to something like rtmp, have Nginx serve it using the device's local ip address (or your ddns of choice). Access web server from my iPad/Phone/PC. I just need to study the hardware side.I also own a 3d printer, so I can definitely create the perfect housing for this, maybe even include some fans.Yihua 8858-V - $19Looks like a decent hot air station for its price, and from a known brand at that. Can't really find another hot air station around this price. Currently getting the version 5, which was probably released around 2022-2023. The only gripe I found online with this one is that some people have a hard time triggering the auto shut off due to the angle the holder has. I could very easily design and 3d print a better-angled holder to alleviate that problem. Or if the filament can't handle the temps, just make an angled base to rest the device, so it leans more and easily activate the auto shut off.HOWEVER, I received a reply from someone who actually ones the 8858 (but maybe not the exact V version) that claimed that this was simply underpowered air volume-wise and burnt their board.So I may have a bit of leeway on the budget for this one as I can see myself using this tool equally as the iron.So far, here are the new models I picked out:RF4-H5 = $75. Got the idea from this post:https://www.eevblog.com/forum/reviews/rf4-1000w-hot-air-rework-station-rf-h2-$125/Forward FW-HA01 = $66. It looks like it's based off of the H5 (or is it the other way around? Both were released around 2-4 months ago). It's not a 100% rebrand, but the knobs, number of memory buttons, heck even the pump looks very familiar to each other. And what even confirms my suspicions is that they almost have the same specs. Both can do 800w, 50L/Min Airflow, brushless turbine fan, 13000r/Min fan speed, 80cm handle. The only difference they have in their specs is that the H5 can do up to 480C, whereas the Forward can do up to 500C. And the H5 uses a Nixie display and the Forward uses a segment display (which I admit to be unfamiliar with, so I asked Claude and it said that the segment is much more durable). Haven't really seen this brand recommended, but they seem to be focused on mobile repair, and have a couple high end products as well. Their website also looks clean and professional (to be fair, as a web dev, you could easily spin up a site like this in less than a week, but I appreciate that they took the time to design it well, use https, and even purchased a .com domain).RF4-H6 = $45Yihua 959D II = $40Yihua 858D = $23Yihua 948DQ-I - $15Nothing much to say. A cheap and decent fume extractor from a known brand. I guess this is better than nothing. I have a 650cfm Dewalt fan (would most definitely not max it though) that I'll angle a bit toward it to help with the air flow and blast any remaining fumes. There's the II and III versions, but they all use the same extractor, the difference is that the latter ones have extra stuff that I already have.Goot GS-104 Medium - $14I was leaning on the SS-02 but found a forum reply @https://www.eevblog.com/forum/reviews/engineer-ss-02-solder-sucker-or-other-nice-desoldering-pumps/of someone who has the SS-02 and Goot pump, and he seemed to lean more towards the Goot.Anker Atom 2 60wI was gonna buy a 100w power bank, but since I only wanna work on pcbs, I decided to just use my existing charger, seeing that pcb work is mostly <=60w.Final thoughtsAs for the flux/solder/attachments for holding the items, I opted not to include them since they're fairly cheap enough to experiment with. Also, some of the brands suggested in this sub aren't available in my country. My plan is to just get the smallest rolls from a couple of brands and practice with them on a test board to see which one is more effective.I really only wanna learn soldering, this wouldn't be used in any commercial capacity, I'm looking at 10-15 hours a week of usage. I'll be happy if this set lasts me 2 years. I think that's enough time to determine if I wanna go ahead and splurge on the big guns. I've already learnt my lesson in spending too much for things that I quickly lost interest in such as power tools, gym equipment (to be fair I still use some), airsoft, drones, cameras, etc." }, { "post_id": "", "author": "K5_489", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "October 05, 2024, 06:15:52 am", "content": "It might just be the old fart in me, but I just don't understand the draw to all these \"smart\" irons, especially so when I see reports of people frying them left and right just from using the wrong USB power supply on them. And then a need to be constantly updating them...how many firmware updates does it take to heat up a stick of steel to a set temp?Reliability you say? I've been using the same Hakko 936 soldering station for almost 20 years now...and for the few times I needed to take a soldering iron to the work instead of the bringing the soldering work to the bench, a Weller butane iron...also for about 20 years.I suppose an argument could be made for a need where 99% of your soldering had to be done off bench...Or if canned butane is a pain to obtain wherever you are.Something I've seen reported time and time again on a lot of these \"off brand\" irons are the tips are absolute garbage, but seem to work well once replaced with genuine Hakko tips, when the irons are built to use Hakko style tips, of course. Which would be one of my big recommendations - get something that uses Hakko style tips. Eventually you're going to want something other than a basic point or chisel tip, and there's a bunch of different sizes & shapes in the Hakko line. Geniune Hakkos are so cheap that there's really no reason to run the clone garbage.I feel genuine Hakko is worth the money, and my first inclination is skip all the extras, get yourself a Hakko soldering station, andhave fun. But I understand budget is budget, and my next thought is to get something like a Yihua 936 or 939. Save a few bucks, roll it towards your next gear buy once you decide yay or nay on this.Fume extractor - you want something that sucks the fumes away, not blowing across your work, especially if you're dealing with SMDs. I know it seems like semantics, but it's important. You also don't need super high airflow for this. All you're after is getting the soldering fumes directed away from your nose so you're not directly inhaling them. Honestly, I don't even bother for most of my work when it's just a quick resistor or cap changeout, and have done tons of work with nothing more than a simple computer case style pancake fan set on edge on my bench.Skip the hot air station for now. There's definitely an art to using one effectively, getting it wrong can quickly destroy a PCB, and you're probably not going to use it much while learning the simple stuff first anyways. This is one of the things you really don't want to cheap out on. You really want something that can blow of LOT of really hot air quickly, so you can get in and melt the solder fast and get back out without heat soaking the parts. Until you get a feel what it takes to melt and flow solder quickly, you're just going to break things with a hot air station to the point of not being able to repair them, and just do it faster with a cheap hot air station.Same with the microscope. You're going to need a good feel for this to begin with, and that's going to be amplified 10 fold when you're dealing with parts tiny enough to need a microscope. Jump right in to that on day 2, and you're likely to just get frustrated enough to want to bin it all and move on to the next hobby." }, { "post_id": "", "author": "JustMeHere", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "October 05, 2024, 07:00:35 am", "content": "Get a real soldering iron. You'll end up spending the same once you factor in a power supply and a cable. You really want silicone cables hooked up to the iron.Spend $75 or more on the iron. Don't worry much about anything else until you learn how to solder. And you don't need much more than an iron, a multimeter, and an inspection loupe for that." }, { "post_id": "", "author": "Solder_Junkie", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "October 05, 2024, 07:46:57 am", "content": "Stick with a proper soldering station, Hakko or Weller. Use only genuine tips and branded solder.A digital camera is hopeless for SMD soldering, you need stereo vision from a binocular microscope. The Swift type with two LED lights is pretty good. Also needed is a low profile PCB holder for SMD work on small boards, such as those used to repair mobile phones.This video shows you all you need to know about hand soldering both through hole and SMD parts.https://youtu.be/eZtPR8_x0nc?feature=sharedSJ" }, { "post_id": "", "author": "SteveThackery", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 05, 2024, 08:09:26 am", "content": "About the microscope. There are two things I can share my experience with. Firstly, make sure the microscope provides enough working space under it. Secondly, lag. One of the mics I bought had a nasty delay in the video feed to the monitor, making it very difficult to work with it. Fine movements are very difficult to control with a delay in your visual feedback loop.Also, there's the problem of 3D. A simple mic plus screen gives you a detailed picture of the work, but with no depth information. Makes you clumsy. That's why I no longer solder like that. For most work I use a good quality \"visor\" with optical glass lenses, and if you haven't used one before it's a transformative experience. Importantly you see in 3D. For the really small stuff I use an optical binocular microscope. Again, you see in 3D, and again it's a transformative experience." }, { "post_id": "", "author": "nmcgann", "author_rank": "Newbie", "is_op": false, "timestamp": "October 05, 2024, 10:33:00 am", "content": "Quote from: Solder_Junkie on October 05, 2024, 07:46:57 amThat is a good video. I’d also recommend the β€œMr Solderfix” channel, there are some great SMT soldering videos on there. I followed his advice and got some 0.25mm solder (lead free) for doing SMT work and that has massively improved the joint quality and consistency I can achieve.I second the good iron+tip+solder advice - I have a Weller TCP station that is 40 years old and a Hakko FX888D that I got recently, both are very good." }, { "post_id": "", "author": "BillyO", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 06, 2024, 02:34:14 am", "content": "LOL! The OP has a budget under $150 and everyone is recommending he spend 5 times that. Folks, not everyone can afford the best equipment in the world .. and they don't need to. I have an old Hakko 936 station and I have an even older Weler. Guess what I use 90% of the time? A FNIRSI HS-01. Yup, a $30 iron. Why? because it heats up faster, maintains temperature better, is smaller and lighter and is cheaper to run. So, it might be easy to brush me off as a know nothing newbie, but no, I've been soldering since I was 10 years old. That's 57 years of experience including at least 10 years doing it as a part of my profession from production line, through production re-work and on to CET.Even a cheap Hakko FX88DX or an equally cheap Weler WE101NA will blow his entire budget, yet they are not great performers compared to something like the $30 HS-01. I know from actual, real experience. Yes, having actually used all of these. To get the performance of something like the HS-01 from a Hakko where the heater and sensor are built right into the tip, and it will heat up from cold in 8 seconds, and from standby in 3 seconds and will shut itself off it you forget for safety and to prolong tip life, you'll need to spend a lot of money. Alotof money. Yes, it will last longer and will perform better, but replacement tips for it cost more than the whole HS-01! And .. he does not have $900 to spend on an iron.My grandfather used to use a soldering iron he heated up in a bed of coals. He swore by it. Made his living with it. No one uses those anymore. Don't knock these little smart irons until you have put them to use for a few hours. They work, and they work well.Let's not get into $900 binocular microscopes!To the OP, your list looks good. It will do what you want and if one of those items is not putting a smile on your face, there are other options you have for replacement when funds permit. Please don't get discouraged by the equipment snobs. The most important thing is for you to get started and your list will get you going. Once on your way you can decide if you enjoy electronics enough to continue and upgrade your equipment or not. I think you are taking the right approach. The only thing I don't think you need to get started is that digital microscope. I can't imagine it would be a great performer. A good magnifying glass you can mount on a retort stand would probably be a better choice for about the same money. Just my opinion and I could be wrong on that as I don't have any experience with that particular DM, but I've had access to similar items that left a lot to be desired." }, { "post_id": "", "author": "shabaz", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "October 06, 2024, 03:05:21 am", "content": "Quote from: BillyO on October 06, 2024, 02:34:14 amUnless some messages are deleted and missing, I don't see that at all. Everyone above appears to have offered suggestions that are well within the budget." }, { "post_id": "", "author": "BillyO", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 06, 2024, 03:14:20 am", "content": "Quote from: shabaz on October 06, 2024, 03:05:21 amOh, really? My mistake.Since you are so sure, please give the model numbers of a Hakko soldering station and a binocular microscope where you can get both for under $150.The absolute cheapest iron you can get from Hakko is $100 and it is and absolute POS. So, now you have to get everything else, including the suggested binocular microscope, for $50. I'll stand by for your revalating response in great anticipation .." }, { "post_id": "", "author": "shabaz", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "October 06, 2024, 04:49:09 am", "content": "One person who suggested a Hakko station advised not to get a microscope for now. Another person explained that a digital camera would be a disappointment and suggested a microscope. I don't think they suggested that the OP should now hold off and not buy a soldering iron until they had saved up a thousand $. They reiterated that a proper soldering station is advised. That's very good advice. Yet another person again advised against a digital microscope, and made the suggestion of a head-mount magnifier. They are excellent.Anway, if someone really did want a binocular microscope immediately, what's wrong with Craigslist/Gumtree type websites? That's precisely how I got my binocular microscope, so it's possible. Even new microscopes do not have to cost a lot; but personally if you ask me (well, even if you don't), I'd advise a second-hand binocular microscope at that sort of a budget. That's if they really need it. A head-magnifier works great and is low-cost; worth the OP considering that (and the good advice that was given) if they have not already done so.You certainly can buy cheap brand new binocular microscopes at low-cost. Is it advised for a beginner? Certainly not, so why even raise a challenge of fitting a $125 budget on that, plus a soldering station?What's with the dumb popcorn and fizzy drink emoticon? It's childish, grow up. You're just being argumentative and that's of no benefit to anyone, especially not the OP." }, { "post_id": "", "author": "JustMeHere", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "October 06, 2024, 08:27:53 am", "content": "Quote from: BillyO on October 06, 2024, 03:14:20 amNot sure why you're copping an attitude. No need here for that.Basically there's no point in buying too many things until the first skill is learned: how to solder.If cheap tools are purchased so \"all\" of the tools are purchased, then the effort becomes self-defeating.Step 1: Get a decent soldering iron and learn how to use it.Don't skip to needing to do anything that requires a microscope until step 1 is accomplished. No need having a microscope until you can do step 1 well. If having the microscope causes step 1 to never be accomplished well, then the microscope should not be bought at the beginner step.Basic project management: when resources are limited, focus on the critical path. Don't spend resources on anything but the critical path. If you spend resources on other things you may never need the other things because you never got past step 1. Microscopes are nice, but you don't really need one. A $10 hand loupe works just fine. The loupe is for inspection. (https://www.walmart.com/ip/Carson-Minibrite-3x-Pocket-Acrylic-Lens-Magnifier-with-Built-in-LED-Light-and-Sliding-Case-Gray-PO-25/11186221?wl13=1383&selectedSellerId=0&wmlspartner=wlpa).Now when you move past the beginner stage and do so much work the loupe is slowing you down then you can consider the microscope. Hopefully at this time you have acquired more resources." }, { "post_id": "", "author": "Ian.M", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 06, 2024, 09:04:11 am", "content": "A combo hot air and soldering iron station (e.g. YIHUA 8786D) is worth considering - not instead of a soldering iron that takes cartridge tips (integrated heater), but in addition to. Hakko 900 style tips are dirt cheap and if they are a decent fit to the element (shim if necessary), the 907 style iron is more than adequate for less demanding soldering tasks + you have less clutter on the bench. Because the tips are cheap you can afford a wider selection. When you encounter a difficult joint, or are out in the field, grab the PTS200 or similar cartridge iron.Also its always good to have min. two irons otherwise what do you do when your one and only iron goes wrong and you need to fix it?" }, { "post_id": "", "author": "xvr", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "October 06, 2024, 01:58:56 pm", "content": "QuoteExactly! I've got my first iron at age 10 (take or give), and microscope at age 40. And I still don't need fume extractor (at age 57). Do not hurry." }, { "post_id": "", "author": "K5_489", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "October 07, 2024, 12:22:44 am", "content": "Quote from: BillyO on October 06, 2024, 02:34:14 amGenuinely curious....how is $60 five times as much as $150? The math doesn't seem to track here, but I'm always open to new ideas..." }, { "post_id": "", "author": "BillyO", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 07, 2024, 12:32:56 am", "content": "Quote from: K5_489 on October 07, 2024, 12:22:44 amWhat is $60? A Hakko soldering station plus binocular microscope (and no, just no, on that plastic thing from the sex toy shop)?" }, { "post_id": "", "author": "Andree Henkel", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "October 07, 2024, 11:27:39 am", "content": "Things you should start with, and which you should notSoldering Iron:YesHot Air Station:No, something for laterMultimeter:Yes, you will need the continous check mode with beep, you need sharp and small tips at your probesdonΒ΄t buy DMM with fixed attached probe cable, but with banana Jacks and included probe cables.fast beep is important. the beep beep thing is just the one thing this \"meter\" needs to do really nice.sice of display and backlighting is not that important for your app, as well as meas modes, digits and accuracy,but: Auto power off is must have, if possible with way to disable, you will curse every timeyou forgot to turn off and battery is emptyMicroscope:No, something for laterMore important is a good light: LED Ring light with *3 magnification, lights your workspace, and for smaller components you look through italso a magnifying glass *7, much cheaper than Β΅sope, you need the money for the ringlightfirst is much more essential than Β΅scope, second will postpone need for Β΅scopeSoldering pump:No, I solder almost every day, and never more need feel need for one, I have sure used them. Only useful if you do a lot of through hole desolderinginstead get a good solder wick, which is essential for SMD, but handles through hole as well:https://www.reichelt.de/de/en/desoldering-wick-1-5-m-1-5-mm-edsyn-sw021-15-p247901.html?r=1this is best I ever used, It is tinned+flux , which greatly improves capillary action compared to just copper+fluxSolder: donΒ΄t underestimate Importance, donΒ΄t buy just cheapest alloy, more expensive ones are especially great for learning soldering, as the appearance of joints is better, so you can learn to evaluate the quality of your solder joints better.First you have to decide unleaded or leaded.I use leaded, to avoid damaging prototypes (like torn pads) by the higher melting temp of unleaded solder.Best leaded solder I use: 0,5mm Diameter, ofcourse flux, eutectic Sn62Pb36Ag2, the 2% silver make a differenceOther stuff needed right at start:*soldererin iron stand - if not included with iron or station*sponge for tip cleaning or wool for this purpose, if not included with Iron / stand*soldering tip tinner*pair of tweezers for holding small components*in case you want to deal with wires:#side cutter#wire stripper" }, { "post_id": "", "author": "Ian.M", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 07, 2024, 12:22:24 pm", "content": "Hot air is increasingly necessary to even work with modern parts. You'll curse any attempts at reworking any SMD IC if you don't have it, and good luck soldering a QFN IC without it - the center pad is essentially unreachable by soldering iron unless its your own board and you design it with one or more large through-plated access holes in the pad, which makes it unsuitable for standard SMD assembly processes. If you aren't interested in component level stuff and only need to solder wires and headers to pre-assembled modules you can do without.Desoldering pump (aka:Solder sucker): *YES* - its good for bulk solder removal not SMD stuff but when you need one the alternative would be to use up desolder braid by the meter! However *DON'T* buy an expensive one. The cheap blue plastic aluminium barrel ones with the machined shaft are entirely adequate for a beginner, provided their plunger O ring is kept lubricated with light silicone oil or silicone spray lube, and only cost a few dollars. DON'T buy one with a pressed U section shaft - they are absolute cr@p - See:https://www.eevblog.com/forum/reviews/need-a-new-solder-sucker-suggestions/The visible difference when buying is a machined step and taper groove right round the shaft up near the plunger cap - if its got it its OK if not its junk!" }, { "post_id": "", "author": "Andree Henkel", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "October 07, 2024, 01:09:07 pm", "content": "regarding Hot air: you are surely right.But he is short on budget.So I suggest to skip hot air and Β΅Scope FOR NOW and spend the money on ringlight, accessoires and better tool quality." }, { "post_id": "", "author": "K5_489", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "October 07, 2024, 07:50:17 pm", "content": "Quote from: BillyO on October 07, 2024, 12:32:56 amQuote from: K5_489 on October 05, 2024, 06:15:52 amhttps://www.amazon.com/YIHUA-Professional-Digital-Soldering-Station/dp/B07RVMZNYR/Yihua 939D+, currently $53.99.Later on in that same post of mine, right after telling OP to skip the hot air station for now -Quote from: K5_489 on October 05, 2024, 06:15:52 amAgain I ask - how is $60 five times as much as $150?" }, { "post_id": "", "author": "BillyO", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 07, 2024, 09:26:05 pm", "content": "Quote from: K5_489 on October 07, 2024, 07:50:17 pmQuit trolling!Quote from: K5_489 on October 05, 2024, 06:15:52 amThis tells me you have no first hand information to share. You also first suggested a Hakko station - minimum ~$150, and it's no great shakes.Someone else suggests a stereoscopic optical microscope - Let's suppose you can get one that has real glass in it's optics used for t$150. I seriously doubt it though. Someone else suggest only use top name-brand solder - There's $65 for a 1lb spool of Kester or the like. Someone else suggests a better DMM, so throw in another $60. What are we at now? $425? Beginning to look like 3x the budget of $125-$150 to me.A single Hakko station that's worth its salt is 5x just by itself.I didn't call any one person out, so why are you trolling me?Just more elitist BS" }, { "post_id": "", "author": "Old Printer", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "October 08, 2024, 12:14:33 am", "content": "Five years or so ago I bought a Hakko FX888D as my first \"solder station\" and I like it very much. Head and shoulders above the standard irons I have used for years. I am sure Weller sells an equivalent. I paid $100 and they are $120 now. I moved up to a FX951 just because I got a good deal on a nice used one. I would recommend something in the class of the FX888, a good quality magnifying visor and a bright flexible work light. I would also skip the lead free stuff, unless you have a very good need for it. Regular solder will be easier for a beginner to work with, the lead free can come later, if at all. Be careful of counterfeits for the Hakko stuff, buy from a known dealer." }, { "post_id": "", "author": "J-R", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 08, 2024, 06:49:30 am", "content": "Another drive-by post. Will the OP ever return to observe the aftermath??There's no denying that if you just want to get some gear to play with on a tight budget, the cheap stuff will get you started. And I think that was made very clear by the OP.Side note, Hakko recently released the updated FX-888DX and the current sale price here in the US is $97.17 with free shipping and gifts:https://hakkousa.com/breast-cancer-awareness-2024-promo1" }, { "post_id": "", "author": "K5_489", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "October 08, 2024, 08:34:38 am", "content": "Quote from: BillyO on October 07, 2024, 09:26:05 pmNo, you didn't call any ONE person out. You quite literally called EVERYONE out, and now are shockingly digging your heels in deep on showing how wrong you can beNow excuse me while I throw away all my perfectly functioning gear to try out some cheap stuff that dozens of people have reported is garbage, just so I too will have \"first hand experience\" to report that it is in fact...garbage.I'd wonder how people like manage to survive on a day to day basis, but there's not enough psychedelics in the world to make it make sense..." }, { "post_id": "", "author": "Aldo22", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 08, 2024, 03:21:02 pm", "content": "Quote from: K5_489 on October 05, 2024, 06:15:52 amThanks for the tip!I had never thought of that before.But I solder too rarely to need an extra device for that.I just tried the handheld vacuum cleaner that I already have.It works perfectly!Absolutely no more fume in my nose." }, { "post_id": "", "author": "K5_489", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "October 08, 2024, 06:51:33 pm", "content": "Quote from: Aldo22 on October 08, 2024, 03:21:02 pmGlad someone found my ramblings useful other than displaying how they can't do math...or read...lolI've done the same thing with a Datavac, with a window exit hole panel I fabricated. The small hose size made it relatively easy to use on the bench without relying solely on the filters to clean the exit air, but I figured if I mentioned that, someone would lose their mind over my \"suggestion\" to use a $500 vacuum for a fume extractor. Little did I know..." } ]
2025-10-17T16:29:23.149606
25
electronics
beginners
true
https://www.eevblog.com/forum/beginners/$200-oscilliscope-any-recommendations-please/
$200 Oscilliscope, Any recommendations please? - Page 1
[ { "post_id": "", "author": "Azhar", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "September 30, 2016, 02:44:03 am", "content": "I need to buy an Oscilloscope, my budget is $200, are there any scopes that you recommend?I need a simple 2 channel scope that do the basic stuff.thanks" }, { "post_id": "", "author": "tautech", "author_rank": "Super Contributor", "is_op": false, "timestamp": "September 30, 2016, 03:43:33 am", "content": "This is the cheapest in the Siglent range if you can stretch to a new DSO for a little more than your budget.http://www.siglentamerica.com/pdxx.aspx?id=26&T=2&tid=1You can get a EEVblog members discount to buy from Saelig.Ask for the discount code in this thread:https://www.eevblog.com/forum/testgear/equipment-discounts-from-saelig/" }, { "post_id": "", "author": "Muttley Snickers", "author_rank": "Unknown", "is_op": false, "timestamp": "September 30, 2016, 04:31:13 am", "content": "The price of $239 on the Siglent seems like a fair deal providing you live in the US, not quite the same ballpark if you need to buy it locally down here though.Trio Test/ Siglent.http://www.triotest.com.au/shop/siglent/2948-siglent-sds1052dl-50mhz-2-channel-widescreen-oscilloscope.htmlUnfortunately as far as a new scope goes you probably wont get much more than a toy down here for $200, some of the Hanteks, Attens/ Grattens go for a little over $300 on Ebay but be careful where you buy one because if found to be faulty or dead on arrival then you might have to pay the postage back overseas just to claim a refund, Paypal required me to send a small item back to Asia using the most expensive postage method they could dream up yet it arrived via the cheapest method possible from interstate.As an example these types of listings below deserve special attention and can be a serious trap for the uninitiated, the items location states Riverwood, NSW, Australia but if the parent Ebay account holder is located elsewhere then that's where the item needs to be returned according to Paypal, this happened in my case with a Hobby King deception so always verify where the item is truly located, where it is to be returned to and any other terms involved even if shipped from what may appear to be a local region." }, { "post_id": "", "author": "danadak", "author_rank": "Super Contributor", "is_op": false, "timestamp": "September 30, 2016, 10:28:25 am", "content": "One way to consider is older Tek 7000 series. You start by getting themainframe + amp + timebase plugins.The advantage is the broad selection of plugins you can buy as necessary,like high gain diff amp, counter, digitizer, spectrum, sampling....very flexible.This approach does not have the sophisticated math and trigger system of a modernscope, but when used in conjunction with a modern scope very useful.http://w140.com/tekwiki/wiki/Main_PageRegards, Dana." }, { "post_id": "", "author": "vk6zgo", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 01, 2016, 08:26:50 am", "content": "If your budget is $200,the best general purpose unit you will get will be a secondhand analog 'scope.The US$400 DSOs often mentioned in this forum get a lot closer to $A700 when you take exchange rates,freight & so on into account.The days of the \"mighty Oz\" being at,& above parity with the greenback are long gone!Unfortunately many eBay sellers,seeing this increase in cost for new DSOs, have also increased their prices for old 'scopes to quite absurd levels.There are still some Oscilloscopes on eBay for sensible prices,though,& there are other sources.Look for Hamfests in your area----they often have a good selection of older test equipment,but sometimes don't.The advantage of Hamfests & other such \"swapmeet\" style meetings is that you can ask to see the device operating.Don't blow all the $200 if you possibly can find a ;scope at around $150 or under." }, { "post_id": "", "author": "tggzzz", "author_rank": "Super Contributor", "is_op": false, "timestamp": "October 01, 2016, 09:15:25 am", "content": "Quote from: vk6zgo on October 01, 2016, 08:26:50 amMake sure it is aworkingscope. Ignore any ebay or other adverts that don't show awaveformoneverychannel. My rule of thumb, here, is Β£1/MHz for a low end scope.For debugging poorly controlled digital signals, 100MHz and higher is preferable. A 20MHz scope can be used for simple well-behaved digital signals (i.e. no signal integrity problems), and for mechatronics.Don't forget that probes are an integral part of makingeverymeasurement. Even cheap/grotty probes will cost as much as a low-end scope." }, { "post_id": "", "author": "CraigHB", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "October 01, 2016, 03:15:09 pm", "content": "Yes $200 is a bit on the low side. You'd have to go with something used. I have a Rigol DSO which cost around 400 USD new. I'm pretty happy with it, though I would like to buy a new once since mine is older and the newer ones have bigger displays. Probably just get another one in the same price range.An analog scope can do most of what you need, but there are some things an analog scope can't do a DSO is really handy for. I actually had an analog scope for the longest time until I finally got the scope I have now. Though now that I've been using it a few years I wouldn't want to go back to analog. A DSO's ability to store waveforms is actually a big help." }, { "post_id": "", "author": "Azhar", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "March 02, 2017, 12:44:18 am", "content": "thanks guys, that was helpful" }, { "post_id": "", "author": "james_s", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 02, 2017, 12:58:06 am", "content": "What kind of stuff do you want to do with it? Do you need a DSO or would an analog scope work for you? It's hard to go wrong with Tektronix, one of my favorite scopes is the 465B, it's old now but still a very capable instrument and a nice one should be able to be had for $200 or less. Ideally look for one that includes a couple of probes, those can be expensive." }, { "post_id": "", "author": "rstofer", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 02, 2017, 01:17:40 am", "content": "I don't know anything about the used equipment market in Australia but here in the US, I bought a used 350 MHz Tek 485 for just $200 about 13 years ago.In looking at eBay today, the prices are around the same with a few very overpriced exceptions. I don't know enough scopes to recommend any particular model but you can search eBay for '100 MHz Oscilloscope' and find MANY scopes including some from GW Instek. But that's over here..." }, { "post_id": "", "author": "Brumby", "author_rank": "Unknown", "is_op": false, "timestamp": "March 02, 2017, 04:38:49 am", "content": "Quote from: rstofer on March 02, 2017, 01:17:40 amThe Australian market is nowhere near that.The population comparison between the USA and Australia is around 15:1 - and the used equipment market would be at least that squared, IMO. Add to that the premium we pay for being where we are and the chances for good deals on good equipment are vary rare.I'm sure anybody from Australia visiting the USA that is shown the best places to look, would want a small container to bring back the gear they would like to grab." }, { "post_id": "", "author": "Brumby", "author_rank": "Unknown", "is_op": false, "timestamp": "March 02, 2017, 04:48:29 am", "content": "Quote from: Muttley Snickers on September 30, 2016, 04:31:13 amI know it's an older post - and I don't know when you had to do the return - but did you know of this?...https://www.paypal.com/webapps/mpp/returnsIt was introduced as a trial mid 2015 IIRC and was made permanent later that same year.Seems it's still active." }, { "post_id": "", "author": "lordvader88", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "March 02, 2017, 11:44:10 am", "content": "If you are lucky, u can get a decent 1980-2000 era 1, working in good shape from ebay for >200.I sort of did, for 200 CAD, at the time maybe 170USDWithout having read the above, I say hold and save your money. Then buy a 500-1200 scopeI would like a? can't remember, but it will cost me +1200, perhaps this summer." }, { "post_id": "", "author": "lordvader88", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "March 02, 2017, 12:00:26 pm", "content": "hEY ALSO FOR $18usd, i JUST ORDERED A DSO138 oscilloscope, from ebay.It's a MINI / POCKET OSCILLOSCOPE, so will go very nice next to my DMMs. So it will very nicely provide a VISUALIZATION of stuff under 200kHz(and really less but thats fine)My 2nd hand, ch1 broken, $200 scope still lays in piecesI worry because I never labeled all the screws, so I have a few I'm not sure where they will go" }, { "post_id": "", "author": "Brumby", "author_rank": "Unknown", "is_op": false, "timestamp": "March 02, 2017, 12:44:04 pm", "content": "Quote from: lordvader88 on March 02, 2017, 12:00:26 pmI got a kit version of that and made it up. It works - but don't expect too much from it and you might be OK with it." }, { "post_id": "", "author": "daybyter", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "March 02, 2017, 01:26:52 pm", "content": "http://www.stm32duino.com/viewtopic.php?t=107" } ]
2025-10-17T19:02:02.998433
16
electronics
beginners
true
https://www.eevblog.com/forum/beginners/$200-power-supply-new-korad-or-used-hp-tektronix-or-similar/
$200 power supply: New KORAD or used HP, Tektronix, or similar? - Page 1
[ { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 07, 2024, 08:59:10 am", "content": "Hello. I trust your experience more than my research. I’m going to spend in the neighborhood of $200 on a power supply. I need/want dual output, up to 30v, not sure about amps. I don’t mind servicing older stuff and actually like vintage stuff that is reliable but need it to work from the start as my project has a timeline. Based on past experience would you buy two KORAD KA3005’s (or comparable) or would you purchase a used, dual output HP, Tektronix, BK or similar off of eBay. I’m new with limited knowledge so if you have other suggestions please feel free to share other possibilities. Any help is appreciated." }, { "post_id": "", "author": "aliarifat794", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "April 07, 2024, 02:52:57 pm", "content": "These brands have a reputation for reliability and performance.Look for models that meet your voltage and current requirements." }, { "post_id": "", "author": "donlisms", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 07, 2024, 03:06:24 pm", "content": "I have bought several used Power Designs, one HP, and one Lambda supply, and had pretty good luck with all of them.The HP needed the most attention - the power switch crumbled; the smoke came when I turned it OFF! Confusing. Not a typical fail, I think. It also has old stiff wiring that needs replacing.The PD's just seem to work; I love them, and would like more, just because I like 'em, not because I need 'em!" }, { "post_id": "", "author": "coromonadalix", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 07, 2024, 03:08:23 pm", "content": "I'm not impressed by Korad .... i would choose any reputable brand well before that one, and if you don't find a dual one, buy two identical models,if it's the case you'll have to fiddle, serial and parallel mode ..Some Mastech and clones had better reliability in the pastDo note, you pay cheap, you'll get cheap" }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 08, 2024, 08:22:09 am", "content": "Quote from: coromonadalix on April 07, 2024, 03:08:23 pmWhat problems did you have with your Korad?" }, { "post_id": "", "author": "voltsandjolts", "author_rank": "Unknown", "is_op": false, "timestamp": "April 08, 2024, 08:31:08 am", "content": "Buy your test equipment second hand, preferably broken (and repairable).You'll lose much less money that way, learn something doing repairs and likely make a small profit when you sell it on." }, { "post_id": "", "author": "psysc0rpi0n", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 08, 2024, 09:01:52 am", "content": "I have 2 Korad KA3005P. For what I do I cannot complain.From what I could check when I purchased them, they are accurate and the only thing that is on the cons is the confusing OCP and OVP buttons and their functions. I recently watched a video of someone trying to figure out how to deal with these 2 buttons and the guy was also quite confused!From minute 18, it starts the struggle with these functions! Other than that, I'm happey with both of them!" }, { "post_id": "", "author": "BILLPOD", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 08, 2024, 12:39:50 pm", "content": "Quote from: psysc0rpi0n on April 08, 2024, 09:01:52 am" }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 09, 2024, 05:26:30 am", "content": "Quote from: donlisms on April 07, 2024, 03:06:24 pmWhat PD models would you recommend for dual output and up to 30V? Also, is Power Designs and Power Designs Precision considered the same quality?" }, { "post_id": "", "author": "donlisms", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 09, 2024, 10:07:35 am", "content": "There are several dual and triple versions, e.g. the TW4005 is a twin 40 volt 0.5 amp model. I don't have one but want one. I have a 6050, single output 60 volts or 5 amps, but not both at the same time!The Precision models, always with those nice four-digit dials, are probably about an order of magnitude more precise. Single output. Specs are 100uV noise and regulation and such; I usually see around 10uV or less, including watching the oven heater switch on and off. (Newer models used LM399.)The precision models are good enough that you start expecting them to be a reference; not to metrology standards, but sub-millivolt easily.Quality... well, I guess... the designs came out of the same brain, but for different purposes. They're all nice.All the PD's are old, no doubt. A little control cleaning might be in order; I keep thinking I should do that someday. Mine just work, except some of the meters. Which I should fix someday, but... no big deal.I should say this: the current limiting adjustment is intended as a safety net, not as a CC supply. The limit is a little vague. In those days, CC wasn't such a normal thing. As best I understand it, you want an infinitely high output impedance for CC and zero for CV, so supplies that try to do both must compromise a little somehow in their output circuitry.I suspect the HP's are similar to the PD's in most ways, including their precision versions (uhm... 6111? 6112? Others?)." }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 09, 2024, 12:37:33 pm", "content": "Quote from: donlisms on April 09, 2024, 10:07:35 amThank you! This is helpful. They've come up in my searches. I like the old school look and assumed (but didn't know) the build quality matched the appearance. I'll include them in my list of options. Gonna have to pull the trigger within the next week or so. I appreciate your input." }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 09, 2024, 12:48:35 pm", "content": "Quote from: MaxBishop on April 07, 2024, 08:59:10 amHave you built or repaired power supplies?What other test equipment do you have?What is your project and timeline?" }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 10, 2024, 05:38:31 am", "content": "Quote from: Electro Fan on April 09, 2024, 12:48:35 pmI haven't built any but I'm gathering parts. I have a few laptop battery packs. I'm intimidated by the thought of it. Is there a build you would recommend? This is all new to me. I don't have anyrealgearother than a couple of voltmeters and an old, currently misplaced oscilloscope that my dad used to use many years ago. My project is already late, lol. I sent a message to an eBay seller tonight on an HP 3620. We'll see what comes of it. If that doesn't pan out there are a few other brands/models I'm watching" }, { "post_id": "", "author": "Wallace Gasiewicz", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 10, 2024, 12:05:35 pm", "content": "About old PS, some of them have an IC that is very hard to find. This chip is the thing that blows, without the chip it is very hard to fix. I have a Lambda like this, I redesigned the control circuits for it but this is a hard thing to do. This is an old Lab Grade Supply with analog meters.I do not know if any of the more modern PS with Digital Meters have this same problem with hard to find reference chips.This is too bad because these old PS have good transformers." }, { "post_id": "", "author": "mr ed", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "April 10, 2024, 09:25:03 pm", "content": "I got fed up with cheap chinese switchers and went with used hp 6236 (6v 2.5a and +/-20v 0.5a ) and 6284 (20v 3a) when the half amp wasn't enough. Get the more recent ones, not the real old ones by Harrison with the colored hp logo. The 6284 has a safety crowbar too. They can be stacked in parallel or series so in principal I can get 60 volts if needed at 0.5a. No fans." }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 12, 2024, 02:59:44 am", "content": "Quote from: MaxBishop on April 10, 2024, 05:38:31 amOKStill not sure what your project is but it sounds like you have something in mind that needs a power supply. Some people like to build a power supply, others are into refurbishing/repairing power supplies - both approaches can be good ways to learn and/or keep the budget down.Having said that, if everything is new to you then I think you might be better off starting with a few pieces of reliable and reasonably accurate pieces of test equipment. If you have a decent power supply and a decent DMM then when you measure V, I, and R you will have some confidence when your measurements and calculations agree, or some reason to relook the measurements and/or calculations if they don’t agree.It depends on how much adventure and experimenting you want to do - but if you are new to electronics and you want to learn and build stuff I’d recommend starting with a few decent tools. Along these lines, a used power supply might save some budget but for about $110 you can get a 30V 5A Korad that will be fairly accurate. Starting with a new working PS from a reliable seller is probably going to be a better experience than starting with a used PS but YMMV. A KA3005D from Amazon can be returned if it isn’t working or doesn’t meet your expectations. I’ve had one for about 10 years and it’s been rock solid; I bought a 2nd unit a couple years ago, and I gave another one as a gift to a new EE. Until you know what else you expect from a PS it’s likely all that’s needed.If you start with one Korad and you really need another PS you can buy a second unit. Sometimes it’s nice to have two of the same pieces of test equipment. You can compare measurements, you will be familiar with the UI on both, and if one is used in another location or is unavailable you have a spare." }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 12, 2024, 05:18:49 am", "content": "Quote from: Electro Fan on April 12, 2024, 02:59:44 amI appreciate you taking the time to provide this feedback! I agree that I should get something that is known to work and go from there. Before I came to that conclusion, I bid on an HP PS on eBay but did not get it. It was kind of the (most recent) final straw for me.My project is simple, but I lack experience and knowledge. I want to make a simple machine surveillance system. Once the initial phase is working well, I’ll add phase two and so on. I’m starting with a Raspberry Pi, some simple diffuse reflective sensors and a bit of coding to count input vs output to get a solid waste count. I didn’t know how to power the sensors, so I Googled it, and it led me here.The power supplies listed here are overkill for what I need to do but now I have the bug and, need it or not I want a capable power supply for future projects. To your point on the Korad, I agree. Yet, I haven’t pulled the trigger because I’m envious of all the cool gear I’ve seen here!As far as my project goes, I was gifted an Allen Bradley 1606-XLP yesterday. It was in a junk pile at work. It is doing what I need for now and it’s affording me time to be picky on my future power supply. The power supply was simply to bench build the system. Acquiring the Allen Bradley was a surprise that, lucky for me, will work for the completed system. The search continues." }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 13, 2024, 08:22:27 pm", "content": "Read Reply #5 and#6 in this thread:https://www.eevblog.com/forum/testgear/are-premium-scope-brands-still-justified/msg5448176/#msg5448176The thread and Reply #5 and #6 are about professional use but the concept applies at some level to enthusiast use also - if you can’t reasonably rely on measurements it can be extra confusing and time consuming." }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 13, 2024, 08:32:23 pm", "content": "Quote from: Electro Fan on April 13, 2024, 08:22:27 pmThank you. More data points for me to consider. There just is no simple path. Well, I guess if funds are abundant that would be a game changer.Maybe, I should be asking the experienced folks here what investment amount is reasonable." }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 13, 2024, 09:50:44 pm", "content": "It’s always good when asking questions here to give context. How much knowledge, experience, skill, budget, etc do you have to apply? What are the objectives, short term and long term? Test Equipment is like a tool - it can help a person solve problems, learn, and have a very enjoyable journey - but it can sometimes be like a drill to make rabbit holes.The question about a β€œreasonable investment” is a good one - but give some thought to that not just for a power supply or two, but for a bench full of test equipment that might surprising populate like rabbits. There are threads here you can find by searching that give advice on what new enthusiasts should consider with respect to various types of test equipment, tools, parts, consumables, etc.The forum members here are super helpful and will try to answer your questions but you will get the best answers when you frame the questions well with your context. Otherwise you might get a lot of enthusiastic answers from someone else’s context. Checkout a thread called β€œTEA”; there might be at least a couple - one short and one long. If you read thoroughly you might find, for example, some people will say you haven’t reached par on oscilloscopes until you have 19.After ~10 years of thoroughly enjoying EEVblog I’m about 15 short of par on oscilloscopes but I’ve made due with just (2) Korad power supplies. That doesn’t mean Korads are right for you - but I’m sure a person can learn a lot and get a lot done with <30 volts and <5 amps if the PS is easy to use, reliable, and accurate to a few hundredths of a volt and a few milliamperes - which the KA3005D is. It will probably be fine out of the box but there is a calibration routine you can use to dial it in with a DMM. But here you see the beginning of the rabbit hole. What if your DMM isn’t accurate?My suggestion would be start with a Korad PS and a couple decent DMMs (so you can measure voltage current at the same time), and climb in the rabbit hole.Once you see voltage and current on your two DMMs agree with the voltage and current readouts on the Korad and all four readouts agree with the calculations you made before hand for your Device Under Test you will be certified to climb in and out of the rabbit hole under your own power - just watch out for TEA symptoms." }, { "post_id": "", "author": "Jwillis", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 13, 2024, 09:53:45 pm", "content": "Mastech power supplies are now VOLTEQ.https://www.volteq.com/. The design has been around for years and are robust, reliable and very easy to repair and calibrate." }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 13, 2024, 10:08:33 pm", "content": "fwiw, I think you want a linear PS and one with a DC output on/off button, not just an AC on/off button. And then you will want to see how cleanly the output turns on and off - which will be the sound of the rabbit hole telling you maybe you need to buy an oscilloscope to see and measure the waveforms.edit: and then you can post your scope’s screen captures of the PS output on/off, at which time you will realize you might need some different probe grounding techniques and accessories to avoid ringing, etc and help you confirm your PS has relatively low ripple, and so on and so forth…." }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 14, 2024, 06:05:47 am", "content": "Quote from: Electro Fan on April 13, 2024, 10:08:33 pmWhat in interesting coincidence. Your timing is spot-on. I've been picking through this post tonight.https://www.eevblog.com/forum/beginners/oscilloscope-training-class-(long)/Mind blown.I can see the rabbit hole ahead, lol. I don't have a good power supply or oscilloscope, that I can find, anyway. I have my dads old scope around here somewhere. Regardless, already I can't seem to settle on just one of either. I have to remind myself this is what I do, jump in with both feet, usually with a fair amount of regret later. So, all the feedback I'm getting is most welcome! So, I have a Fluke, I believe it's a 17B or similar and a Klein Tools CL210. Hopefully, that's a decent set of starter DMM's. i can't seem to settle on the vintage power supply I want to purchase so I'm good with the KORAD. Quick question on that... I'm assuming the difference between programmable vs non programmable is well worth the $24 difference. Any thoughts on that are welcome." }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 14, 2024, 01:05:15 pm", "content": "Given your questions and comments I don’t think you will regret jumping into the rabbit hole - but to get the best experience I suggest using a good ladder.The trick to getting a ladder that will enable an ee (non-degreed electrical enthusiast) to safely and enjoyably climb in and out of the rabbit hole, imo, is to get well grounded (haha) in Ohm’s Law. This means doing enough simple math to understand and reasonably predict the relationships that result from V=IR.Print the wheel and post it near your bench.https://www.formulacalculators.com/ohms-law-calculator/DC is a good place to start, then when you get to AC you can build on the foundational concepts and math learned with DC. AC will add things like RMS. Along the way you will start to recognize the concept of reactance as you distinguish impedance from simple resistance. The oscilloscope can help you visualize some of this and if it has useful math or measurement readouts the scope can help you connect the wave form insights to measurement insights. Things like Peak to Peak vs average vs RMS and 50 ohms vs 1 M ohms will start to show up over and over like markers on your rabbit hole ladder. This is a long way of saying you don’t need an expensive DMM but I’d get one with TRMS vs average RMS. When you see numbers like .707, 1.414, and 2.828 in your dreams you will know you are making progressAnd when this chart makes sense you will be another ladder rung proficiently into the rabbit hole.https://www.minicircuits.com/app/AN40-012.pdffwiw, from an early rabbit hole journey:https://www.eevblog.com/forum/testgear/fluke-17b-rms/For high voltage stuff, get a Fluke or Brymen. For low voltage stuff get one or two Aneng 8008 (save money and get good features with surprisingly good accuracy).The KA3005P adds the programmable PC interface and won’t cost much more than the KA3005D (but you might find the software a tad primitive). Both the D and P offer excellent value for the price.As for scopes, just take the elevator into the rabbit hole, get off on the Siglent floor marked HD.This advice is intended to save you time and money. Enjoy the journey, it is likely to be fascinating.edit: Maybe add one Aneng 8008 from Amazon to your Fluke and Klein collection and you are set on DMMs." }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 15, 2024, 05:12:31 pm", "content": "Quote from: Electro Fan on April 14, 2024, 01:05:15 pmThis is all a bit intimidating... SOOO much information! I downloaded the charts. Thank you. After looking closer at the Fluke 17b I am wondering if that is actually the model I have. If it is I didn't realize it is so capable. When I return I'll have a look. As for the scope, I just don't know if I can manage something new in the budget. Even the 804 @ $439 is steep for my (initial) plans. And, it is out of stock, currently. When watching the Oscilloscope training vids I had myself convinced a used Tektronix would suffice. Is that not a good route to take? I'm a bit weary of buying used for such an important tool but I feel if I wait for the perfect tool at the perfect price I may never get started. Thoughts?* This advice is intended to save you time and money.Your consideration is much appreciated! Thank you." }, { "post_id": "", "author": "donlisms", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 15, 2024, 07:47:39 pm", "content": "There are many people who can't imagine relying on an analog Tektronix scope; it's not even digital! It does depend a lot on what you're doing, of course, and there are many people who *do* rely on them. I prefer my 485 as daily driver, unless or until there is some feature I need on the cheap digital scope.As to the fear of the unknown... you'd want to try and get as good a sense as possible of how well it's working before you buy, though there is always risk. I have a couple that were in great shape, and a couple that need work. The nice thing about it is the manuals are readily available and amazingly helpful. And while there may be obscure parts that fail, my guess is that you'd mostly need standard things like... capacitors. Plus there is a helpful community of experience out there. And videos. IOW, my view is once again \"don't be scared.\" :-)I also very firmly believe that your projects in your bench will tell you when it's time to get more gear, as opposed to trying to predict the future and what you might need someday. This is not necessarily a popular view, and doesn't always line up well with the Joy of Acquisition of New Shiny Baubles!" }, { "post_id": "", "author": "wizard69", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 16, 2024, 12:49:44 am", "content": "Quote from: MaxBishop on April 07, 2024, 08:59:10 amThat really isn't a lot of money to buy new. In fact I wouldn't bother with a lab supply.QuoteTimelines imply a project that is for money in most cases. As such it might make sense allocating more money for new hardware. On the flip side a project implies that you might know the exact voltages and currents required. If so fixed voltage industrial/commercial supplies are very cheap. You can literally find hundreds of such supplies from the regular distributors and they can be cheap.QuoteThere are numerous suppliers of lab type variable voltage supplies and they often come up for sale or auction. You can also go a bit upscale and get supplies used in test and measurement systems, often surprisingly cheap on auction or used. However the lack of information related to what makes this a pressing need really means we can't offer ideal advice." }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 16, 2024, 02:36:27 am", "content": "Quote from: MaxBishop on April 15, 2024, 05:12:31 pmStill not sure what your project and overall objectives are but I’d recommend making it fun and educational.One easy low cost way to do that if you are just getting started is to stick with DC circuits until you get comfortable with Ohm’s Law. For this you can postpone an oscilloscope.Just get the Korad and use your existing DMM(s). Get a couple breadboards, a package of LEDs, and an assortment of resistors, plus some 22 gauge solid wire, and a wire stripper - all easy to get on Amazon. Make simple circuits in various combinations until you can predict (calculate) what voltages and resistances will result in what current as shown on the Korad readouts and as confirmed on your DMM(s).Watch some youtubes and post your breadboard layouts and test results and questions here. Total investment less than $200 including the power supply. (Or to really save on the budget just use a 9V battery - but I think the flexibility and functionality of the power supply will speed up the learning process and make it more fun).When you get Ohm’s Law working as expected you can move on to capacitors or maybe transistors or other components, or maybe try an Arduino if you are interested in digital and software. Lots of cool and useful stuff can be learned and built without an oscilloscope. If you go this route and decide you need or want a scope you can revisit the used analog vs new digital vs bothdiscussion. Enjoy the journey." }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 19, 2024, 05:31:13 am", "content": "Quote from: wizard69 on April 16, 2024, 12:49:44 amThank you for the feedback, wizard69. My initial plan was to buy all used gear but it is looking like I may buy the KORAD for future testing but, for this project I'm using an Allen Bradley power supply.It isn’t something I’ll get paid for. Not the work I’ll put into it, anyway. It is something I want to use at work, though. Specifically, I want to prove there are other options than cost prohibitive industrial surveillance systems. I’ve considered using a PLC but I don’t know anything about the programming languages typically used.It’s only pressing because I’ve put a tentative completion date on it." }, { "post_id": "", "author": "MaxBishop", "author_rank": "Contributor", "is_op": true, "timestamp": "April 19, 2024, 05:39:52 am", "content": "Quote from: Electro Fan on April 16, 2024, 02:36:27 amThank you, Electro Fan. This sounds like a great plan for me. I'm going to utilize many of your suggestions. As far as my project, it's embarrassingly simple. I want to make a production machine surveillance system. The first step will be to count production pieces, input with one sensor and output with the other. Then, with some basic programming I can determine the % waste (raw material). If that all goes well, I’ll add another sensor at a different location in the process." }, { "post_id": "", "author": "Electro Fan", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2024, 12:24:53 pm", "content": "Maybe just learn/experiment/prototype with an β€œArduino sensor kit” fromAmazon. An alternative to the oscilloscope would be a low cost (~$20) logic analyzer from Amazon or eBay plus free Pulseview software. The Arduino or Rasberry Pi are excellent platforms for learning the intersection of electronics hardware and software; Arduino is a notch easier if you haven’t done much/any coding. You can power the Arduino from a computer USB cable as you program it, so even the Korad could move to Phase II. If you get TEA syndrome you will probably recognize the symptoms.https://sigrok.org/wiki/PulseView" } ]
2025-10-17T16:37:02.725598
31
electronics
beginners
true
https://www.eevblog.com/forum/beginners/$250-or-less-100mhz-oscilloscope/
$250 or less 100mhz oscilloscope? - Page 1
[ { "post_id": "", "author": "iLearn", "author_rank": "Newbie", "is_op": true, "timestamp": "July 11, 2013, 05:21:48 pm", "content": "Hi EEV Blog community.I'm looking for my first oscilloscope to use on car projects and hopefully any car-related engineering projects when I start graduate school next semester (mechanical engineering). I read the rave reviews about the Rigol 50mhz being hacked to 100mhz, but even that is above my $250 budget.So, I wanted to ask you more experienced folks, what are some good 100mhz oscilloscope options for $250 or less in this new 2013 year? (the more portable the better)I'm also open to any diy kits as long as they have beginner-friendly build instructions." }, { "post_id": "", "author": "ddavidebor", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 11, 2013, 05:45:24 pm", "content": "All the analog you want, or some old hp with vey limited sample rate." }, { "post_id": "", "author": "dfmischler", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "July 11, 2013, 06:19:46 pm", "content": "I bought a Tektronix TDS380 oscilloscope (2 channel, 400MHz, 2GSa/s, 1kpt) on ebay for less than $250. With shipping. But it takes patience and knowing enough to decide what is a good deal when you see it." }, { "post_id": "", "author": "iLearn", "author_rank": "Newbie", "is_op": true, "timestamp": "July 11, 2013, 08:45:56 pm", "content": "Quote from: dfmischler on July 11, 2013, 06:19:46 pmThank you for your input guys and this is why I'm asking you more experienced EEVBloggers. I'm a beginner, but I want to get something that won't limit me 1-2 years from now as I become more knowledgeable in engineering and small electronic projects. I understand the Rigol DS1052E has been out a while now, is there a better 2013 alternative?(yes, I've searched the forum, but need some help since I'm a n00b)" }, { "post_id": "", "author": "marshallh", "author_rank": "Unknown", "is_op": false, "timestamp": "July 11, 2013, 10:47:54 pm", "content": "Quote from: dfmischler on July 11, 2013, 06:19:46 pmThe one in israel? Haha I linked that one to a few people." }, { "post_id": "", "author": "dfmischler", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "July 12, 2013, 12:29:31 am", "content": "Quote from: marshallh on July 11, 2013, 10:47:54 pmNo. Mine was purchased in, I think, 2010. Shipping from Israel to the USA would probably be a deal killer..." }, { "post_id": "", "author": "Chalky", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "July 12, 2013, 02:52:11 am", "content": "Quote from: iLearn on July 11, 2013, 05:21:48 pmHow about portability? I bought a Fluke 123 portable scope, which is great for cars, but the guy who sold it reckons that Picoscope is the way to go. Never used one of those myself, just thought worth mentioning." }, { "post_id": "", "author": "iloveelectronics", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "July 12, 2013, 04:33:39 am", "content": "I don't think you will be able to find any new 100MHz DSO for under $250, except for some unknown Chinese brands before any shipping fee is added. Your best bet would be to find some used equipment." }, { "post_id": "", "author": "Corporate666", "author_rank": "Unknown", "is_op": false, "timestamp": "July 12, 2013, 09:03:36 pm", "content": "There is no brand new scope with 100Mhz capability and some portability for <$250 - just not going to happen.Do you really need 100Mhz capability? I can't see many (any?) situations where that would be needed for automotive work." }, { "post_id": "", "author": "PA4TIM", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 12, 2013, 11:42:31 pm", "content": "100 mHz ? Just place a very good Low Pass filter and you can use any scope that has a 1 sec/div timebase. A DSO would be best. Otherwise you only see a slow moving dot.Sorry, could not resist it. It is MHz. 1 mHz is 0.001 Hz.Buy a good secondhand analog Tek instead of a Chinese toy scope." }, { "post_id": "", "author": "iLearn", "author_rank": "Newbie", "is_op": true, "timestamp": "July 14, 2013, 09:49:25 pm", "content": "Ok guys,how about the best bang/buck PC USB oscilloscope with 100MHz accurate bandwidth?Recently, I'm playing with PropScope. It's very visually-comfortable to use because my laptop monitor is much bigger than most dso display screens. Unfortunately, the propscope is not accurate to 100MHZ..http://www.parallax.com/go/propscope" }, { "post_id": "", "author": "Unknown", "author_rank": "Unknown", "is_op": false, "timestamp": "July 14, 2013, 10:28:16 pm", "content": "25 MS/s would be good for a few MHz real-time bandwidth. From what I gather from the extremely limited specs, its vertical range is also extremely limited (1/2/10/20 V full scale). Yet another toy.Some Picoscope models might be suitable for your application, but they're not going to be under $250. And the UI still sucks compared to a stand-alone scope for general purpose use. In my opinion, either pony up cash for a real DSO (DS1102E would probably be the cheapest that I would consider), or" }, { "post_id": "", "author": "iLearn", "author_rank": "Newbie", "is_op": true, "timestamp": "July 15, 2013, 02:12:43 am", "content": "Thank you to those of you who contributed your valuable and experienced advice.Per your advice, I've decided to wait a little more and buy something when I have a budget of ~$400. At the $400-$500 (USD) range, which 100MHz oscilloscopes do you guys recommend(including the PC-USB based interface ones)that have a bigger display screen compared to Rigol while also being battery powered and somewhat portable?" }, { "post_id": "", "author": "iLearn", "author_rank": "Newbie", "is_op": true, "timestamp": "August 03, 2013, 10:33:56 pm", "content": "I just purchased a Rigol DS1052E that is still in 50Mhz mode, but it feels like great quality and I'm excited to learn everything about it!Currently, I'm educating myself on all the functions and will test everything. One thing I'm pleasantly surprised is the fact that it's much more portable than I anticipated.YES, I have my 1st oscilloscope, woohoo!Btw, are there any fun automotive applications any of you have used this oscilliscope on for fun and testing, etc?" }, { "post_id": "", "author": "Chalky", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "August 03, 2013, 11:45:58 pm", "content": "Quote from: iLearn on August 03, 2013, 10:33:56 pmGood choice! In-car automotive is a bit hard with that scope unless you're able to run a mains lead out to the car - I used a portable scope recently when I was proving that my power windows were not causing significant drop in the voltage level at my bluetooth car kit." }, { "post_id": "", "author": "iLearn", "author_rank": "Newbie", "is_op": true, "timestamp": "August 13, 2013, 07:30:08 pm", "content": "Hey guys (and gals),are there any good oscilloscope tests you can recommend me beside what's in the manual to make sure this oscilloscope is working 100% perfect?" }, { "post_id": "", "author": "dfmischler", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "August 13, 2013, 07:52:39 pm", "content": "The classic test is to feed the scope a square wave or pulse edge with a fast rise time. Sub nanosecond would do it. The scope should show the edge rising at the scope's maximum slew rate (which for a 50 MHz scope should take around 7 nanoseconds or less)." } ]
2025-10-17T20:18:22.435442
17
electronics
beginners
true
https://www.eevblog.com/forum/beginners/$49-hitachi-v-1100a-for-repairs/
$49 Hitachi V-1100A for repairs - Page 1
[ { "post_id": "", "author": "jakeottinger", "author_rank": "Contributor", "is_op": true, "timestamp": "June 29, 2016, 02:47:56 am", "content": "Hi guys and gals,I know it's not the best practice to be a newb and buy an oscilloscope that needs repairs but Looking at the photos I assumed the thing had been dropped on it's face and knobs were broken and that's all that was wrong. I powered it up and everything seems to work. I figured it would be a simple fix. However I'm having trouble sourcing the pots and knobs for this thing. Attached is a photo of the unit.Any ideas on where where to get these pots? I'm afraid to take it apart at the moment since my bench is a total mess and I'd enevitably loose parts until I clean up.Thanks for any and all replies!" }, { "post_id": "", "author": "tautech", "author_rank": "Super Contributor", "is_op": false, "timestamp": "June 29, 2016, 04:07:21 am", "content": "Bugger, that's a shame it's so beat up.In the service manual the BOM may have clues to the value of the pots, type (lin or log) and the original supplier.http://elektrotanya.com/hitachi_v1100a_v1070a.pdf/download.html11.6 MBWait for \"processing\" to change to \"get manual\"." }, { "post_id": "", "author": "jakeottinger", "author_rank": "Contributor", "is_op": true, "timestamp": "June 29, 2016, 04:20:19 am", "content": "Thanks for the tip on waiting for Processing. I saw this page before but found no way to download. I guess I just had to wait a bit." }, { "post_id": "", "author": "jakeottinger", "author_rank": "Contributor", "is_op": true, "timestamp": "July 08, 2016, 12:47:10 am", "content": "So one of the destroyed pots is a RV2701 part number 8410393 EWK-ANAS 10k+10k. Where the heck can I find that? google only shows phone number reverse lookup for some reason. It's the level control without wich I'm assuming triggering will not happen. Do you think a stereo pot will work? It looks like a stereo footprint. Any Ideas? Thanks guys/ gals" }, { "post_id": "", "author": "neko efecktz", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "July 08, 2016, 02:07:08 am", "content": "Just a suggestion.Possibly find one of the same model online in a \"not working condition\" and salvage the parts from that.if there is board damage you may also be able to salvage boards from the Not Working unit.In the dropped unit check heavy components on the boards and especially the transformer.Bill." }, { "post_id": "", "author": "edavid", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 08, 2016, 02:13:34 am", "content": "Quote from: jakeottinger on July 08, 2016, 12:47:10 amIt's a dual concentric pot, not a single shaft pot like a normal stereo pot. (If you used a single shaft pot, you would have the same A and B trigger levels, which might not be so bad.)" }, { "post_id": "", "author": "jakeottinger", "author_rank": "Contributor", "is_op": true, "timestamp": "July 08, 2016, 05:44:36 am", "content": "I'm starting to doubt the ability of my go to supplier." }, { "post_id": "", "author": "jakeottinger", "author_rank": "Contributor", "is_op": true, "timestamp": "July 08, 2016, 05:49:48 am", "content": "@edavid do you happen to know if that pot is linear or log? Or at least how to test lin vs. log to find out?" }, { "post_id": "", "author": "jakeottinger", "author_rank": "Contributor", "is_op": true, "timestamp": "July 08, 2016, 06:01:19 am", "content": "@neko I already bought a non-working o scope, I understand the suggestion but I'm not about to buy another. I'd rather fix this one. Plus the only other Hitachi 1100A's out there sell for 4X the price I paid for this one. I'd much rather solder parts than steal them from other units that cost much more than I paid. I have thought about buying another donor but just can't bring myself to admit defeat just yet..." }, { "post_id": "", "author": "tautech", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 08, 2016, 06:17:27 am", "content": "How good are you at mechanical repairs?Could the pot shafts be repaired?Some closeups of the removed pot might spur some ideas rather than trying to find something that's hard to obtain." }, { "post_id": "", "author": "jakeottinger", "author_rank": "Contributor", "is_op": true, "timestamp": "July 08, 2016, 06:22:53 am", "content": "https://www.dropbox.com/s/11jl68sas9p76k3/20160707_231934.jpg?dl=0sorry for the bad photography but the outer shell is completely severed." }, { "post_id": "", "author": "edavid", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 08, 2016, 03:19:29 pm", "content": "Quote from: jakeottinger on July 08, 2016, 05:49:48 amI would think linear, since zero trigger level is in the center... it's very unusual to find a log pot in a scope." } ]
2025-10-17T19:15:35.479565
12
electronics
beginners
true
https://www.eevblog.com/forum/beginners/$50-hot-air-station/
$50 Hot Air Station - Page 1
[ { "post_id": "", "author": "daveyk", "author_rank": "Frequent Contributor", "is_op": true, "timestamp": "April 30, 2017, 12:43:25 am", "content": "Anyone have experience with these $50 hot air stations? Heck they look nice:https://www.ebay.com/itm/191557453776Sent from my iPhone using Tapatalk" }, { "post_id": "", "author": "Brumby", "author_rank": "Unknown", "is_op": false, "timestamp": "April 30, 2017, 01:30:57 am", "content": "I have something similar for about 2 years now. The hot air seems reasonable. However the iron on mine is not crash hot. There is a significant air gap between the element and the tip, which really messes up the thermal capacity, so it doesn't get usedmuch(at all, really) - especially when I have a better iron on the bench. When I bought the unit, I looked at getting a spare element and found it was different to similar irons and while you can get replacements, they are not nearly as common. Haven't needed to replace the element yet - but that's hardly surprising since I don't use the iron. I have thought about getting a better iron that is electrically compatible - but I'm not motivated to muck around with that since I have a better iron right next to it. So I pretty much only use if for hot air.The iron also had one small issue which showed the level of quality of the unit:When I pointed this out to the seller, we went through a little dance on how to deal with it, which eventually worked out to me getting a partial refund. I bought a replacement plug from Jaycar to swap over, but I haven't fitted it yet.I did do the \"Don't turn it on, take it apart!\" to check out the internal construction - always a good idea on cheap Chinese stuff. While it wasn't aerospace quality, it was reasonable for the price and - more importantly - safe enough to use.It doesn't get a lot of use - but seems to be functional. You get what you pay for." }, { "post_id": "", "author": "Jono427", "author_rank": "Contributor", "is_op": false, "timestamp": "May 01, 2017, 02:31:25 pm", "content": "Looks like the hot air is the same (or similar) to this stand alone one. I grabbed a similar one, but haven't done work with it yet (just heat shrink). As Brumby said \"Don't turn it on, take it apart!\" - just look at the thread below too. Mine was fine and better than what Dave got in hid video.https://www.eevblog.com/forum/chat/deadly-wiring-fault-atten-858d-hot-air-rework-station/" }, { "post_id": "", "author": "WaveyDipole", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "May 03, 2017, 10:43:44 am", "content": "I've had my 858D for a few months now although I have only used it a handful of times so am still a relative novice. Since I already have a decent Weller iron, I only needed the hot air gun rather than a complete station. Besides, since my desk space is very limited, the less space used the better. I did take mine apart to examine before first use and did find a couple of problems. In particular, the fuse was on the neutral rather than the live AC input line so even if the fuse blew, the circuit would have been left connected to live. Also its worth checking all ground connections. However these issues are not difficult to fix. I initially practiced on a couple of old boards that I hadn't yet disposed of to get the hang of using it, although I'm still trying to get a feel for the optimum temperature and fan speed settings, which I'm sure will come with more experience. I think it does seem to depend to some extent on the type of solder used on the board but for most part seems to work very well. I also find that you have to leave it running for 3-4 minutes to get up to temperature properly before using it." } ]
2025-10-17T18:57:20.645853
4
electronics
beginners
true
https://www.eevblog.com/forum/beginners/$500-multimeter-recommendation/
$500 multimeter recommendation - Page 1
[ { "post_id": "", "author": "headingwest", "author_rank": "Newbie", "is_op": true, "timestamp": "April 19, 2013, 03:04:07 am", "content": "Hi All,My better half has offered to buy me good multimeter, AUD$500'ish budget. What would your top recommendations be?I've been using the Victor 86E - a lovely chinese product - but it's time to step up a bit.Thanks for your help." }, { "post_id": "", "author": "Lightages", "author_rank": "Unknown", "is_op": false, "timestamp": "April 19, 2013, 03:14:55 am", "content": "I guess you have to ask yourself what you want to do. $500 might be much better spent on two multimeters. One is not enough many times and four can be required for some things.If you really must spend $500 on only one multimeter then a nice one would be this:http://www.testequipmentdepot.com/agilent/multimeters/u1252b.htmHard to beat it for features and quality.If you think you might want to have two meters then I would suggest a Brymen BM869 and a Brymen BM257 both with their optional USB cables. Two great meters, both with good safety with the BM869 having the highest safety rating in the industry.Of course there is Fluke......" }, { "post_id": "", "author": "c4757p", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 03:23:15 am", "content": "If you're looking in the $500 range, then I'm going to adamantly insist on two $250 multimeters. There's not much you're going to get in the $500 meter that the $250 one won't have. Go for dataloggers if you can find decent ones." }, { "post_id": "", "author": "Fsck", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 03:27:09 am", "content": "Are you limited to just one meter or the budget?(I'd hope the budget)If handheld, I'd get 2 decent meters. Not sure what the market is like, but for that price (in Canada), you can get anywhere between 2 to 4 secondhand Fluke 87 types. Or something like a U1272a + UT61E or a BM869 + UT61E.I'd personally probably go with a BM867 with logging kit+ 2*UT61E. (this fits if we convert AUD to CAD and buy shipped to Canada)" }, { "post_id": "", "author": "Ferroto", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 19, 2013, 03:36:54 am", "content": "You can get yourself a Rigol 1052E for less then $500. I'd just stick with a Fluke 87, $500 bucks is abit much to spend on a meter." }, { "post_id": "", "author": "BravoV", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 03:39:13 am", "content": "I think its better to tell us a bit about your self like are you hobbyist, electrician etc, and your normal usage for this new upcoming meter." }, { "post_id": "", "author": "jmole", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "April 19, 2013, 03:42:26 am", "content": "unless you're considering a bench meter, you should look into those handheld scopemeters by fluke. Believe you can pick up a used one on ebay for around $500 depending on the model." }, { "post_id": "", "author": "free_electron", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 04:32:06 am", "content": "for that price you can get two 34401 meters on ebay.can't go wrong with those..." }, { "post_id": "", "author": "headingwest", "author_rank": "Newbie", "is_op": true, "timestamp": "April 19, 2013, 04:38:48 am", "content": "I'm a keen hobbyist with one years experience working with microchips and small boards. Mains voltage for testing faulty equipment but not design.I need to repair the coffee machines we import:http://www.coffeemachine.com.au/product/hlf-fusion/I am working revision 3 of a control board to let android phones control coffee machines:http://divapid.com/While trying to build a robot - like most hobbyist are:http://jimsrobot.com/So what do I really need:instructions in English - I'm sick of guessing what the manual sayslogging preferredprecise small voltage / currentdigital troubleshooting toolsplus stuff I haven't thought of yet but will need in the next few yearsnew not second hand - it's a gifta very understanding wife" }, { "post_id": "", "author": "Lightages", "author_rank": "Unknown", "is_op": false, "timestamp": "April 19, 2013, 05:14:27 am", "content": "Based on what you want to do I repeat my recommendation for these two meters:http://www.tme.eu/en/details/bm257/portable-digital-multimeters/brymen/#$111 USD plus shippingplus the USB cable for logging when you need it:http://www.tme.eu/en/details/kitbrua-20x/meters-software/brymen/$31 USD plus shippingor get it from Franky, iloveelectronics here on this forum, when he gets it back in stock for $135 shippedplus he has the USB cable too when he has the BM257 in stock, I forget the pricePlus get the Brymen BM869:http://www.tme.eu/en/details/bm869/portable-digital-multimeters/brymen/#$240 USD plus shippingand the USB cable:http://www.tme.eu/en/details/kitbu-86x/meters-software/brymen/$52 plus shippingAll in it should come under the $500 price including the shipping.With these two really well built meters you will be able to have high accuracy and high safety plus the logging of both meters at the same time to a computer. The dual temp measurement of the BM869 will come in handy with the coffee machines as will the high safety of the meters when you are poking around the high power heater controls.So you will be able to log current and voltage at the same time and figure out power, or log voltage or current vs temperatures, etc....The BM869 is for high accuracy and high resolution and with dual temperatures, and the BM257 is the small one for poking around in smaller places and has a non-contact voltage detector to let you know if you have a live circuit before you actually touch something. Both should take a beating." }, { "post_id": "", "author": "Ed.Kloonk", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 07:28:08 am", "content": "Yeah also want to say, for $500, go with two (different) meters. Unless you have a reason to need one meter worth half a grand." }, { "post_id": "", "author": "M. AndrΓ‘s", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 08:29:02 am", "content": "Quote from: free_electron on April 19, 2013, 04:32:06 ami dont find any of them below 500 on ebay" }, { "post_id": "", "author": "Fsck", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 08:41:55 am", "content": "Quote from: M. AndrΓ‘s on April 19, 2013, 08:29:02 amme either" }, { "post_id": "", "author": "KJDS", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 09:26:10 am", "content": "Quote from: Fsck on April 19, 2013, 08:41:55 am^^^Wot e Sed^^^Usually at least Β£350 each" }, { "post_id": "", "author": "BravoV", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 09:36:53 am", "content": "Its obvious Vincent did his last ebay transaction at yester-years." }, { "post_id": "", "author": "eevblogfan", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 19, 2013, 09:39:07 am", "content": "heysorry but I think you went nut'soplease have a look at the lovely 2'nd hand HP3478Acan be easly picked up for 100~150$ , so 2 can easly be bought ,and besides , If you need two top end multimeters for that price ( and new ) I'll suggest buying 2X 87V from some ebay seller , you can easly tell one that he'll do 2 for 500$ including shipping , I did found one for 147$ including shipping but that's rear , so please go for one of those , I would but some 3610A and two 3478A if I was you ,Cheers !" }, { "post_id": "", "author": "bingo600", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 12:16:52 pm", "content": "Quote from: headingwest on April 19, 2013, 04:38:48 amnew not second hand - it's a giftWell the New criteria , prob. rules out any 6.5 digit meter.The understanding wife ... Is prob gonna cost more than $500 (in shoes)/Bingo" }, { "post_id": "", "author": "ddavidebor", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 12:28:26 pm", "content": "I suggest you a good fluke or agilent plus an hp 34401aSo you have one strong and portable, and another one advanced and super accurate" }, { "post_id": "", "author": "commongrounder", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 19, 2013, 07:19:42 pm", "content": "Fluke 289. Hands down best. Logging with trendplot built in. Measures just about everything. I treasure mine." }, { "post_id": "", "author": "olsenn", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 19, 2013, 08:12:30 pm", "content": "Check out the Rigol DM3058E (http://www.rigolna.com/products/digital-multimeters/dm3000/dm3058E/). It costs $449 new, and is definitely your best choice unless you get a steal off some used Agilent stuff on eBay. The DM3058E is the same as the regular DM3058 except it doesn't offer GBIB or LAN connectivity (It still can be controlled remotely via USB or RS232).It is 5 1/2 Digits, 0.015% DCV accuracy; 240,000 count, and 123 readings/sec. It has extremely advanced features for a DMM including histogram plotting and other statistical analysis, can measures in dbm and other less commonly used formats when desired, features all the common measurements as well as capacitance, junction (diode) voltage, frequency, custom sensors; it has a continuity buzzer, and the display is pretty nice.If you are looking for a handheld meter, I'd highly recommend looking for a used Fluke 87 on eBay, or even a 28-II. One thing I would recommend though, if purchasing used, is to pick up some precision voltage references from TI free samples page to ensure basic calibration. Some precision resistors can also come in handy for calibrating resistance/current measurements." }, { "post_id": "", "author": "kxenos", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 19, 2013, 10:50:13 pm", "content": "My beloved Beauty I Take Care Honestly off, decided (after speaking with her mother, I believe) that our family budget can afford a bench multimeter some months ago, so I bought a Keithley 2000 from ebay. There is also a forum member that sells a keithley 2015 in a very reasonable price, if he still has it. My point is, if you have a chance to get something of 500$ don't waste the opportunity for things that you could get anytime. Plus a decent bench DMM is a nice bit of kit to have." }, { "post_id": "", "author": "bingo600", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 19, 2013, 10:56:25 pm", "content": "Quote from: kxenos on April 19, 2013, 10:50:13 pmI can only second that , and i got a 2055 from KJDShttps://www.eevblog.com/forum/reviews/keithley-2015-teardown/msg213757/#msg213757It was calibrated in May 2011 , and is spot on my 10v Geller reference.Just get a probe set from ebay or ... If you decide to get the 2015 , there's just the 2015 in the package./Bingo" }, { "post_id": "", "author": "Lightages", "author_rank": "Unknown", "is_op": false, "timestamp": "April 19, 2013, 11:09:29 pm", "content": "You guys keep missing one important point. He said NO USED EQUIPMENT.A new Fluke 289 is $600+A Fluke 87V is a nice meter but lacking some features for the price.The Brymens I mentioned cost less together with the PC cables and software than the Fluke alone. Two meters and each with PC software for less than the price of one 87V. It seems a no brainer to me and you can't beat the safety rating of the Brymen BM869. It is built to very high standards and is very accurate too." }, { "post_id": "", "author": "ddavidebor", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 20, 2013, 08:36:44 am", "content": "Used precision 5+ digit multimeter are much better than new" }, { "post_id": "", "author": "EEVblog", "author_rank": "Unknown", "is_op": false, "timestamp": "April 20, 2013, 08:47:20 am", "content": "Quote from: headingwest on April 19, 2013, 03:04:07 amAgilent U1272Ahttp://www.triosmartcal.com.au/2251-agilent-u1272a-dmm-digit-water-dust-resist.html" }, { "post_id": "", "author": "bingo600", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 20, 2013, 05:19:16 pm", "content": "Quote from: EEVblog on April 20, 2013, 08:47:20 amI'd check if the PSU + Free meter also applies to OZhttp://uk.farnell.com/agilent-technologies/e3610a-u1272a/bundle-psu-bench-30w-free-u1272a/dp/2250753Almost reachable for$500/Bingo" }, { "post_id": "", "author": "Lightages", "author_rank": "Unknown", "is_op": false, "timestamp": "April 20, 2013, 10:09:46 pm", "content": "Quote from: EEVblog on April 20, 2013, 08:47:20 amAh c'mon Dave! We are trying to get him to follow your advice to get two meters!" }, { "post_id": "", "author": "ddavidebor", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 21, 2013, 11:46:25 am", "content": "I have the solution!!!Buy a 250$ meter and use the remaining 250$ for buy something sweet for your girlfriend-wife" }, { "post_id": "", "author": "EEVblog", "author_rank": "Unknown", "is_op": false, "timestamp": "April 21, 2013, 11:49:03 am", "content": "Quote from: Lightages on April 20, 2013, 10:09:46 pmBut he asked for ONE!Hardly anyone in here gave him the advice he was asking for, so I did" }, { "post_id": "", "author": "Ed.Kloonk", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 21, 2013, 12:12:20 pm", "content": "Quote from: EEVblog on April 21, 2013, 11:49:03 amTrue dat. A few of the accessories on the linked page and you're pretty spot-on I thought." }, { "post_id": "", "author": "ivan747", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 21, 2013, 04:24:37 pm", "content": "Remember this is a gift, SO, when you pick your gifts you generally do not ask for:Used stuffThings that weren't offered to you (getting 2 meters instead of 1, a scope etc.)Extra accesories (but that is not a strict convention)That's how I see it." }, { "post_id": "", "author": "Lightages", "author_rank": "Unknown", "is_op": false, "timestamp": "April 21, 2013, 04:38:52 pm", "content": "I did suggest the U1252B!That would be my preference for ONE meter." }, { "post_id": "", "author": "ivan747", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 21, 2013, 07:45:48 pm", "content": "It all depends on his needs, really." }, { "post_id": "", "author": "olsenn", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "April 21, 2013, 07:58:02 pm", "content": "I'm still sticking to the DM3058E, haha; but if he's specifically looking for a handheld that Agilent should do nicely (I still prefer Fluke, what both are great meters)." }, { "post_id": "", "author": "nanofrog", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 21, 2013, 08:00:31 pm", "content": "Quote from: Lightages on April 21, 2013, 04:38:52 pm+1" }, { "post_id": "", "author": "ddavidebor", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 21, 2013, 09:52:26 pm", "content": "People, and an high end gossen metrawatt?" }, { "post_id": "", "author": "EEVblog", "author_rank": "Unknown", "is_op": false, "timestamp": "April 21, 2013, 10:13:17 pm", "content": "Quote from: ivan747 on April 21, 2013, 04:24:37 pmYep, and he's from Oz. So it's gotta be from an Oz supplier, or possibly ebay (but why would you do that and get no warranty?)So what would go get if offered ONE meter up to the value of AU$500?I vote the U1272A. Feature packed, and you get a nice cal certificate with values." }, { "post_id": "", "author": "Lightages", "author_rank": "Unknown", "is_op": false, "timestamp": "April 21, 2013, 11:06:37 pm", "content": "Just curious Dave, why the U1272A over the U1252B for you?" }, { "post_id": "", "author": "peter.mitchell", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 22, 2013, 08:42:37 am", "content": "I WAS going to suggest the Gossen Metrahit Energy, because it can do volts + amps at the same time, so it's like getting two metersthen i looked at the price D:" }, { "post_id": "", "author": "EEVblog", "author_rank": "Unknown", "is_op": false, "timestamp": "April 22, 2013, 09:17:13 am", "content": "Quote from: Lightages on April 21, 2013, 11:06:37 pm- Completely new design- More rugged- Better IP rating- Low Z mode- Smart Ohm mode- tighter count spec- 300 hours vs 36 hours battery" }, { "post_id": "", "author": "Wytnucls", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 22, 2013, 09:21:12 am", "content": "...and the big one: internal data logging. 10,000 versus 100 points only for the 1252B.Also, CAT rating up to 3000 meters and there is a BT module available." }, { "post_id": "", "author": "EEVblog", "author_rank": "Unknown", "is_op": false, "timestamp": "April 22, 2013, 09:31:01 am", "content": "Quote from: Wytnucls on April 22, 2013, 09:21:12 amI think the BT is available for both.Complete no-brainer though really, U1272A wins hands down." }, { "post_id": "", "author": "Wytnucls", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 22, 2013, 09:46:11 am", "content": "Features in favor of the 1252B:50,000 count on both displays (dual display)Square wave generatorCapacitance 100mF high range instead of 10mF on the 1272Aand yes, the BT adapter is available for both." }, { "post_id": "", "author": "Lightages", "author_rank": "Unknown", "is_op": false, "timestamp": "April 22, 2013, 06:57:50 pm", "content": "It looks like it comes down to personal preference. But seeing as I have never seen nor used either I only have a weak opinion this one." }, { "post_id": "", "author": "mark5009", "author_rank": "Contributor", "is_op": false, "timestamp": "April 24, 2013, 10:21:38 am", "content": "I'm also from Oz (Sydney). I got a used Fluke 8842A (no RMS module) delivered for around $200 from eBay. 5-1/2 digits and lovely to use. Then you have $300 left over to get yourself something else, perhaps newer? But, unless you have a good idea of what you are after, maybe second hand and flexible is the way to go?.. m." }, { "post_id": "", "author": "EEVblog", "author_rank": "Unknown", "is_op": false, "timestamp": "April 24, 2013, 10:49:19 am", "content": "Quote from: Wytnucls on April 22, 2013, 09:46:11 amNot close to making up for the poor battery life and other stuff IMO." }, { "post_id": "", "author": "nanofrog", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 24, 2013, 04:46:30 pm", "content": "Quote from: EEVblog on April 24, 2013, 10:49:19 amFWIW, I don't find it much of an issue for bench use. But I keep an eye on the battery indicator (I've figured out how low I can go before the meter to goes flakey), and swap it for a fresh one.For field work OTOH, I could see it as a notable issue." }, { "post_id": "", "author": "Lightages", "author_rank": "Unknown", "is_op": false, "timestamp": "April 24, 2013, 05:32:54 pm", "content": "Hmmm, I thought your many complaints about the U1272A in your review would make it less of a recommendation.The annoying beepOff position on the dial (personal preference)Buggy firmwarePulse measurement error with DC offsetCapacitor measurement \"big fail\" on low caps, and errors on others \"way out there\"Overload protection recovery problemsYeah the battery life on the U1252B is horrible, but it will use a rechargeable and you can leave it on charge anytime you aren't using it. It doesn't log like the U1272A. It does have other features the 1272 doesn't. Maybe it has firmware bugs too but they haven't been mentioned that I can remember.Actually, for either of these, $400+ they should be damn near perfect. I see little to criticize on my Brymen BM869. It just works and has no bugs and has a higher CAT rating too!Maybe he should just get the Fluke 87V and be done with it." } ]
2025-10-17T20:23:24.041427
48
electronics
beginners
true
https://www.eevblog.com/forum/beginners/$55arduino-replaces-$18k-labview/
:: ... $55arduino replaces ... $18k labview - Page 1
[ { "post_id": "", "author": "3roomlab", "author_rank": "Frequent Contributor", "is_op": true, "timestamp": "March 01, 2015, 12:26:36 pm", "content": "so i was bored, randomly reading things off internet ... and then i read thishttp://pheloniusfriar.dreamwidth.org/45390.htmlwe would all expect expensive high tech stuff to be well supported ... but then again LOLz happened" }, { "post_id": "", "author": "electr_peter", "author_rank": "Unknown", "is_op": false, "timestamp": "March 01, 2015, 02:15:31 pm", "content": "One guy who is not happy about $18,000 National Instruments 2.26 GHz Quad-Core Labview DAQ systemIt is a clear example of \"In some situation it does not matter what it is called or how much it costs as long as it works.\"" }, { "post_id": "", "author": "SL4P", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 01, 2015, 02:22:52 pm", "content": "I used to work for a large minicomputer manufacturer, and while technology marches on, and implementing more powerful hardware is not a problem because of price--- I'm amazed at what a lot of people don't know is possible with an 8/16-bit PIC or Arduino platform.If you flip back 30 years - there were multi-user 'mini-frame' systems with 20 or 30 concurrent users, disk, printing, and other activities - running on a processor/memory that was comparable to a high-end ATMEGA or PIC16 chipset.Maybe it's something they put in the coffee at university CS/SE cafeterias?" }, { "post_id": "", "author": "Seekonk", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 01, 2015, 04:07:48 pm", "content": "I remember when people were trying to convince me to use a Data General DOS 1.05 instead of a 486 PC, that sounds so quaint now" }, { "post_id": "", "author": "3roomlab", "author_rank": "Frequent Contributor", "is_op": true, "timestamp": "March 01, 2015, 09:16:36 pm", "content": "i wonder if NI came around to fix their embarassment ..." }, { "post_id": "", "author": "SL4P", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 01, 2015, 09:36:59 pm", "content": "NI gear is well made and respected (or it used to be), but has always been cantankerous and fragile to setup and keep running.Really intended for set & forget applications. If you breathe on it, something will fall over!" }, { "post_id": "", "author": "max_torque", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 02, 2015, 12:26:14 pm", "content": "So it seems that if you just need to do a simple task, then a simple solution is, er, simpler..... wow who'd of thought it eh! ;-)(ie, both an $10 arduino and a $100M super computer can flash an LED, if that's all you want to do. But if you want to say decrypt 1000 parallel streams of 128b SSL encoding in near real time, then the arduino isn't going to perform quite so well)" }, { "post_id": "", "author": "tszaboo", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 02, 2015, 04:35:03 pm", "content": "Quote from: electr_peter on March 01, 2015, 02:15:31 pmI think that picture summarizes what I think about NI." }, { "post_id": "", "author": "Sigmoid", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "March 02, 2015, 05:02:02 pm", "content": "$55?!Someone got robbed, apparently." }, { "post_id": "", "author": "3roomlab", "author_rank": "Frequent Contributor", "is_op": true, "timestamp": "March 02, 2015, 05:24:30 pm", "content": "Quote from: NANDBlog on March 02, 2015, 04:35:03 pmgeez ... they are that bad huh? or the bosses skimped and didnt hire enough support engineers ... i would think its the guy up there insidei have a friend who happen to visit google some years back, he said the work environment is ... like wow." }, { "post_id": "", "author": "mtdoc", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 02, 2015, 05:39:11 pm", "content": "Sounds like a bit like just using the right tool for the job.From the other side:In the early 1990's I was in charge of running an undergraduate neurobiology lab course at UC Berkeley. We had one lab exercise that involved doing EEGs and measuring evoked potentials. They had been using the same dedicated EEG set up for 25+years. The equipment was far outdated and there was only one set up to share between all the students. I was tasked with finding a modern replacement.I contacted several companies making EEG equipment - all with complete solutions, costing about $30K for one set up. These were designed for medical use. There was nothing designed for a teaching lab that had the sophistication to measure the kind of evoked potentials we wanted.So - I did some research and found out that NI data Acquisition boards could be installed in the new Mac computers we were just then about to purchase for student use. For about $2K for LabVIew and $500 each for the DAQ boards we could potentially have numerous setups to do what we needed.I spent the next 6 months learning LabView and developing the application for the lab. It was a great success. We saved $25K and now had 5 setups instead of one and with a student friendly computer interface.Furthermore I went on to use DAQ boards with more computers on carts and Labview to develop other \"virtual intstruments\" to replace some outdated traditional hardware for other lab courses.Clearly NI products and LabView are not the right tool for every job but for some jobs it is and can actually result in a large savings spent on lab equipment." }, { "post_id": "", "author": "3roomlab", "author_rank": "Frequent Contributor", "is_op": true, "timestamp": "March 02, 2015, 05:43:14 pm", "content": "maybe the part which they implemented required very specific tolerances (smashing atoms!) ... and the NI engineer assign have no clue ... nanovolts?what kind of measurement ranges did you involve? mtdoc?" }, { "post_id": "", "author": "mtdoc", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 02, 2015, 06:11:34 pm", "content": "Quote from: 3roomlab on March 02, 2015, 05:43:14 pmWell, it was microvolts to millivolt range amplitude,with up to kHz frequencies -so nothing super high speed. We did need minimum 12 bit amplitude resolution as I recall.We didAuditory Brainstem Responseand other types ofsensory evoked potentialssuch as visual and somatosensory.We also didp300 evoked potentialsNone of these required super hi speed DAQ but they did require custom software to coordinate the stimulus with the acquisition, average out noise over several thousand samples, etc. This was being run with the PC hardware of the era (i.e. donkey slow compared to todays hardware)." }, { "post_id": "", "author": "CatalinaWOW", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 02, 2015, 06:22:16 pm", "content": "Seems like someone missed the boat in not being fully Labview conversant before going to a limited time expensive one shot test opportunity. It is nice that the Arduino interface was able to save the day, and if he had to learn Arduino on the spot it is a nice plug for the Arduino interface, but not something I would want to bet my coveted time window on." }, { "post_id": "", "author": "electr_peter", "author_rank": "Unknown", "is_op": false, "timestamp": "March 02, 2015, 06:28:03 pm", "content": "This story is an obvious case of the right tool for the job.Sometimes you use a tool and find you have exhausted it in one or another way, specs simply are slightly lower than what you need. Other times tool are just too expensive/hard to use/time consuming/overcomplicated/too heavy/etc. but it could do the job.Original story has more details. Equipment used in a experiment was an absolute mess - clever engineers just try to do what they can to accomplish the required goals. NI instrument in question was used for one of weird integration functions and failed in that situation. It was mentioned that experiment setup was tried first time and will be improved and more integrated in future.NI instrument was an overkill in this story and it failed to do some designated function which was replaced with overpriced ($55) Arduino board. Scientist/engineer was flipping a bird at NI because of very demanding schedule on the site." }, { "post_id": "", "author": "Dave Turner", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "March 02, 2015, 07:32:59 pm", "content": "Now that's a Macgyver" }, { "post_id": "", "author": "Harrkev", "author_rank": "Contributor", "is_op": false, "timestamp": "March 04, 2015, 10:06:23 pm", "content": "Quote from: Sigmoid on March 02, 2015, 05:02:02 pmIf you RTFA, that included an Ethernet shield. So, no, not really." } ]
2025-10-17T19:46:05.908912
17
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(-bjt-amplifier-circuit-v_be-negative-)/
[ BJT amplifier circuit, v_be negative ] - Page 1
[ { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "March 04, 2012, 04:17:39 pm", "content": "Hi,I am learning about BJT transistor and I understand them quite well know... I guesseduntil I saw the following simple circuit:http://www.reconnsworld.com/audio_simplepreamp.htmlWhat I do not understand: passed the first AC coupling capacitor, the voltage can benegative. Usually, the transistor is base voltage biased in such a way there is an offsetso that negative voltages are not an issue. But in this schema, there is no offset. I builtit, and it works: I get some Vbe < 0 and get a correct Vc with no clipping...How is it possible, can someone explain to me what I am missing? I guess there issomething with a current involved from Vcc to C1 as the voltage accross C1 becomes< 0, and that it acts as the Vbe offset I do not see... but not clear at all to me.Thanks!Best regards,texane." }, { "post_id": "", "author": "Tube_Dude", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "March 04, 2012, 05:40:10 pm", "content": "HiTake out of circuit C1, and check, if then, you have around 0,6 Volts VBE, if not, or you have a faulty transistor, faulty R3/R2, or wiring error..." }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "March 04, 2012, 05:51:04 pm", "content": "Thanks for answering.I think I found my mistake... I left the oscilloscpoe to AC coupling and obviously was seeing'negative' voltages instead of the real one... for my defense, let say this is an old scopeOf course, having Vbe negative would have clipped the voltage on the other end.Best regards,Fabien." }, { "post_id": "", "author": "Tube_Dude", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "March 04, 2012, 05:54:10 pm", "content": "Happy End!!" }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "March 04, 2012, 05:55:57 pm", "content": "yes, but I spent a lot of time thinking that my understanding of BJT was wrong or incomplete...still a lot to learn by the way" }, { "post_id": "", "author": "Tube_Dude", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "March 04, 2012, 06:03:33 pm", "content": "We all (almost all...), learn with our mistakes..." } ]
2025-10-17T20:35:36.405688
6
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(-comparator-with-npn-transistors-)/
[ comparator with npn transistors ] - Page 1
[ { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "January 17, 2010, 08:36:50 am", "content": "Hi,I am working on a small project forwhich I need to compare a voltageto 2.5v. The compared voltage iscalled Vin. If Vin is more than 2.5,I need a Vout to 5V, otherwise to 0V.I do not want to use a comparator,but transistors for learning purposes.I was thinking about using the avoltage divider so that Vin is scaledfrom [0, 5 volts] to [0, 1.4] thus mycomparing voltage become 0.7v (ie.was 2.5v in [0,5] becomes 0.7v in[0,1.4]) which I plug to an opampwhich is linked to the transistor Basepin.< 0.7v wont switch the transistor ON,otherwise it will. I can replace the opampwith another transistor.Is the basic idea good? Any commentwelcome! I have read relying on theBaseEmitter voltage drop is not a goodthing...Thanks for helping," }, { "post_id": "", "author": "Unknown", "author_rank": "Unknown", "is_op": false, "timestamp": "January 17, 2010, 12:12:49 pm", "content": "You want to use an OpAmp, but not a comperator?I'll tell you a secret. A comperator is an OpAmp, just specially optimised for working as a comperator. So I don't see the learning experience here - replacing a comperator (which is an OpAmp) with an OpAmp, albeit one not specially suited for comparing." }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "January 17, 2010, 02:32:43 pm", "content": "hi,forget about the opamp, and replace itwith a transistor providing the samevoltage (ie. Ve = Vb - 0.6) but with again in current. My question was aboutrelying upon the drop of 0.6v (0.7v) atVbe.Thanks,f." }, { "post_id": "", "author": "Zero999", "author_rank": "Super Contributor", "is_op": false, "timestamp": "January 17, 2010, 05:53:11 pm", "content": "You'll need several transistors, not just one.Google for 'differential pair' and learn the basics of differential amplifiers which is what goes into op-amps and comparators.Look at the datasheet for a comparator and op-amp IC and base your design on it.Accept, that your circuit will never be as good as an IC because none of the transistors are matched." }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "January 17, 2010, 06:03:59 pm", "content": "ok, thanks for pointing me to the right direction.Thanks," } ]
2025-10-17T20:43:45.214286
5
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(-different-grounds-)/
[ different grounds ] - Page 1
[ { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 19, 2010, 02:09:28 pm", "content": "hi people,let say I have a device D0 I want tomonitor the clock and data signals.The device is powered by a 5v/10Macurrent source I have no access to(except to power D0 of course)To monitor the signals, I plan to usea pic microcontroller. Let call itD1. I will have to power it withanother current source.Let say the D0 signal frequencies arefar below the one the pic can handle,so no problem for that point.My question: since the ground is notthe same in the 2 cases (cannot powerD0 and D1 from the same source), howcan I measure a D0 voltage from D1?Am I misleading?The question may be basic, but I donthave any clue... was thinking aboutsomething like a relay, but it wouldnot be possible due to relatively highfreqs...Thanks for answering,Regards," }, { "post_id": "", "author": "jahonen", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 19, 2010, 03:25:32 pm", "content": "How much voltage difference you have between the grounds? If it is not extreme (less than 1 kV), then maybe AD/TI digital isolators are the solution you are looking for. Optoisolator is also possible but problem there is a rather large drive current required by the optoisolator LED.Or, if the ground voltage difference is only a few volts, then even a RS-485/422 receiver / ordinary comparator may work.Regards,Janne" }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 20, 2010, 07:15:14 am", "content": "Hi,Thanks for replying.Some friends told me that by linkin the2 grounds together, it will do the job, ieI will be able to measure both voltages.But I don t understand it...with this newmixed ground, how can the Vcc remainon the same value?Would you have any link, ref, course...handling this kind of topics? (ie. having2 current and voltage sources inside thesame circuit?)Regards," }, { "post_id": "", "author": "mkissin", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "February 20, 2010, 10:41:39 am", "content": "As long as you connect the ground of D0 and D1 together, your PIC will be able to read the other digital signals from D0 just fine. It actually doesn't matter that they are being powered by two different sources.All voltages in electronics are relative. As long as all your devices agree on what voltage to call zero, it works. Only when they cannot agree on the zero voltage level do you need an isolation barrier.I'm assuming, though, that your PIC is also being powered with a 5V source. If it's not, then you would also need to be careful that it will accept the 5V logic levels used by D0 (i.e. a 3.3V PIC probably wouldn't accept 5V logic, unless you used current limiting resistors or level translators)." }, { "post_id": "", "author": "jahonen", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 20, 2010, 11:50:53 am", "content": "Connecting the grounds together is easiest solution, but that is not always possible due to isolation/ground voltage difference or safety reasons.Vcc does not need to be exactly same for both circuits, but one must make sure that levels are compatible so that logic levels are correct. Small voltage differences are usually not significant.Regards,Janne" }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 21, 2010, 10:20:18 am", "content": "Hi,Thanks for replying, your answers are of greathelp since I have hard time understanding somekey concepts (more of a software guy...)I think I understood all this, I will confirm bypracticing a bit...Regards,Fabien." }, { "post_id": "", "author": "Simon", "author_rank": "Unknown", "is_op": false, "timestamp": "February 26, 2010, 09:30:33 pm", "content": "you should be able to connect the two grounds together, he you could even connect VCC of one to the ground of the other but that would make it difficult for the the circuits to interact, ground is essentially just that the 0 and reference point, provising it is actually negative (or even if not) you can connect it to your main earth, providing you don't connect two power delivering lines together at the same time. if your sampling one circuit with you pic circuit ensure you are not in a position where two voltages will clash, this is ually avoided by making a connection between the two via a pullup resistor and/or IC's that have an output transistor with an unconnected collector so that the two supplies never \"meet\" directly." } ]
2025-10-17T20:43:38.063355
7
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(-high-(gt20kv)-back-emf-suppression-)/
[ high (>20KV) back EMF suppression ] - Page 1
[ { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "April 03, 2012, 05:43:24 am", "content": "Hi,I am working on a project where I load capa then discharge them rapidlyin a coil using a MOSFET to produce a high magnetic field. To be efficient, oneconstraint is to make the field as short (in time) as possible. Thus, di/dt isvery high, and the back EMF can reach up to 20kV... and I did not find any'flyback' diode that can handle such a voltage. I found some monster diodesthat can handle 6kV, but they burned up during the first test ... :/I try to change the switching MOSFET by an IBGT, but same problem asabove.Maybe there are some well known techniques to address this issue, and yourhelp would be very appreciatedCheers,Fabien." }, { "post_id": "", "author": "Psi", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 03, 2012, 06:35:45 am", "content": "Maybe look at TVS diodes or MOVs" }, { "post_id": "", "author": "TerminalJack505", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 03, 2012, 09:01:18 am", "content": "Your diode will try to clamp the voltage at about a volt so the problem is really the current. More precisely, the power that's dissipated by the diode.You can try a diode with a higher power rating.And/or you can clamp at a higher voltage by putting several diodes in series. This will spread the power dissipation equally across the diodes.A small value resistor in series with the diode is another option. This will limit the current but raise the voltage." }, { "post_id": "", "author": "BravoV", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 03, 2012, 09:10:39 am", "content": "Quote from: TerminalJack505 on April 03, 2012, 09:01:18 amWill a series of diodes also increase the total break down voltage proportionally ?" }, { "post_id": "", "author": "TerminalJack505", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 03, 2012, 09:19:14 am", "content": "Quote from: BravoV on April 03, 2012, 09:10:39 amAs in the reverse breakdown? That I don't know.It shouldn't problem in this particular case, though." }, { "post_id": "", "author": "Neilm", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 03, 2012, 06:32:40 pm", "content": "There are some high voltage diodes used for rectifying at high voltages but they are not that easily available. One I have seen is the SL500 that can take 5kV. I think that it does go up to 12kV. I don't know how much power they can take. I have seen diodes that go up higher than that (>20kV) but I don't know the part number for that. I also don't know where you could get it. I used these in a project and ended up speaking to specialist distributors.YoursNeil" }, { "post_id": "", "author": "IanB", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 03, 2012, 06:52:22 pm", "content": "Do you have a circuit diagram? I don't understand where your diodes are placed and what function they are performing.(For example, back EMF suppression usually involves putting a diode in parallel with the coil to shunt the collapsing field current away from the rest of the circuit and prevent an EMF building up. What is the configuration here and why does the diode need 20 kV capability?)" }, { "post_id": "", "author": "TerminalJack505", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 03, 2012, 06:53:43 pm", "content": "I'm confused as to why everyone seems to think the diode needs to have a high voltage rating. The voltage rating of the diode just needs to be greater than the voltage that the capacitors are charged-up to before dumping their current into the inductor.The whole purpose of the flyback diode is to prevent the EMF voltage spiking up to, in this case, 20kV. It does this by clamping the voltage at its forward voltage, Vf. This will just be a volt or two in this particular case.So I'm pretty sure what is killing the diode is the heat dissipated during flyback. If the current through the inductor was 10A when the MOSFET was turned off then this 10A is going to flow through the diode. 10A * 2V is 20W of power, which the diode turns into heat." }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "April 06, 2012, 11:12:03 am", "content": "Hi,Thanks for your replies.I join you a partial schema, but I have to take a look at theactual capa value so that I can compute the actual currentand the power that needs to be dissipated by the diode, asTerminalJack505 suggests." }, { "post_id": "", "author": "ejeffrey", "author_rank": "Super Contributor", "is_op": false, "timestamp": "April 06, 2012, 12:47:44 pm", "content": "Assuming the capacitor and inductor are lossless (i.e., worst case), the peak current through the diode is:Imax = V * sqrt(C/L)The peak power (given the diode forward drop is Vf) is:Pmax = Imax * Vfand the total energy per pulse absorbed by the diode is:Qd = 0.5 * C * V^2And the decay time of the field is:t_decay = sqrt(L*C) * V/Vf" } ]
2025-10-17T20:34:47.996745
10
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(-switching-5v-on-off-with-3-3v-command-)/
[ switching 5v on off with 3.3v command ] - Page 1
[ { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "June 09, 2013, 06:18:04 pm", "content": "Hi,I need to switch on off a 5v source using 3.3v command (ARM MCU GPIOs).The load can draw up to 2A, typically 500mA. In this application, frequency andrising times can be omit (the source is switched on or off by a human).One constraint is that the analog switch must be in serie between the sourceand the load (high side design).I planed to use a P channel MOSFET, but looking at various datasheets showtypical Vgs threshold voltages in [2 - 4]v. 2v is too close, as 5v - 3.3v = 1.7v, andI am looking for a Vgs threshold more in the [3.5 - 4]v range, or some dedicatedIC that specifically fits this purpose ... Have you any reference?Currently, what I do is to use a N channel MOSFET to convert the [0 - 3.3v] to[5v - 0v] and use it to control the second P channel MOSFET. But it makes 2FETs.Thanks for your help!" }, { "post_id": "", "author": "jmole", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "June 09, 2013, 06:21:03 pm", "content": "Why not use a low-side switch?" }, { "post_id": "", "author": "c4757p", "author_rank": "Super Contributor", "is_op": false, "timestamp": "June 09, 2013, 06:22:56 pm", "content": "Quote from: texane on June 09, 2013, 06:18:04 pmOh no, two FETs!Sounds like a perfectly acceptable solution to me. Why would you rather use a dedicated IC than two cheap-ass FETs?Quote from: jmole on June 09, 2013, 06:21:03 pmI second this, though. Are yousureit has to be high-side?" }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "June 09, 2013, 06:34:43 pm", "content": "Hi,Thanks for your replies.Being high side is a requirement in this circuit. I thought some specializedand low cost ICs did exist for this kind of application, but the 2 FETs solutionis fine too." }, { "post_id": "", "author": "c4757p", "author_rank": "Super Contributor", "is_op": false, "timestamp": "June 09, 2013, 06:40:18 pm", "content": "I'm sure there are specialized ICs for this, but it's hard to beat the price of a little FET. Out of curiosity, why high side?" }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "June 09, 2013, 06:54:44 pm", "content": "This is part of the specs: currents not returning to the ground mustalso be switched off. That is why the switch is high side." }, { "post_id": "", "author": "David_AVD", "author_rank": "Super Contributor", "is_op": false, "timestamp": "June 09, 2013, 09:45:26 pm", "content": "You could also check out some of the \"load switch\" ICs that are around. Some of them should be in the current range you want." }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "June 10, 2013, 05:43:03 am", "content": "Thanks for the tip, it helps a lot. The ICs I see all have a voltage drop betweenthe gate and source of max. 0.2V ... it can be an issue." }, { "post_id": "", "author": "AndyC_772", "author_rank": "Super Contributor", "is_op": false, "timestamp": "June 10, 2013, 06:07:00 am", "content": "Is the pin of your MCU 5V tolerant? If so, perhaps you could pull it up to 5V with a resistor, connect it to the gate of your P-FET, and program the pin into open drain mode." }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "June 10, 2013, 06:33:10 am", "content": "Thanks for the advice. I will have a look at the datasheet to see if GPIOs are 5v tolerants." } ]
2025-10-17T20:21:21.725273
10
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(-ttl-output-to-cmos-input-)/
[ ttl output to cmos input ] - Page 1
[ { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "November 14, 2009, 01:42:03 pm", "content": "Hi,I am to interface an old TTL based device withthe PIC18f. The device has roughly 20 pins comingfrom TTL based gates I have to read at a given time.I did not know, but reading the PIC18f specs, someof the GPIOs are CMOS Schmitt trigger input buffer indigital IO mode. So I guess I have to translate the level,from TTL to CMOS, because the TTL level may be toolow for the CMOS Schmitt trigger to switch correctly, Iam right?In that case, do you know about a chip doing so?Cheers,Fabien." }, { "post_id": "", "author": "jimmc", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "November 14, 2009, 03:50:02 pm", "content": "A pull-up resistor from the TTL output to VCCwill ensure that VOHis CMOS compatible.Value is not critical, say 4k7 lower for high speed operation. Minimum value is set by IOLmax of TTL device.For ultimate speed use 74ACT series device (eg 74ACT04 hex inverter) as a level shifter, the ACTseries has TTL compatible input thresholds.Jim" }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "November 14, 2009, 05:52:58 pm", "content": "Hi,Thanks for replying. I do not really care aboutspeed in this application. I did see the trick ofadding a pullup resistor, but I do not understandit... I understand what a pullup resistor is I mean,but could you explain why it raises the voltagein this case? I mean 2 voltages from differentsnodes do not add...Thanks for helping,Fabien." }, { "post_id": "", "author": "septer012", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "November 14, 2009, 06:06:20 pm", "content": "Maybe you need something like this?!http://www.sparkfun.com/commerce/product_info.php?products_id=8745I used one for a 3.3v GPS to 5v PIC/Shmidt Trigger Input" }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "November 14, 2009, 07:07:05 pm", "content": "Thanks, I will have a look. At a first glanceit seems a bit undersized since I would needat least 6 pins, thus an octal buffer converter.Cheers,fabien." }, { "post_id": "", "author": "jimmc", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "November 14, 2009, 07:09:49 pm", "content": "The standard TTL output stage is the 'Totem pole' shown here:http://www.siliconfareast.com/ttl.htmas you can see that, on its own, the output cannot rise above 2 diode drops below VCC.Adding the pull-up resistor enables the output to rise to VCCwhen the lower transistor (T4) is off.Under these conditions the diode is reverse biased and T3 has no effect.If you're not interested in speed the a higher value resistor may be used for the pull-up, it only has to overcome leakage in the TTL output stage, 22k will still give 4v with almost 50uA of leakage.I am assuming that you are running the PIC from the 5v, the TTL only operates at 5v.A quick Google on 'TTL to CMOS' gives this as one of the top results:http://www.fairchildsemi.com/an/AN/AN-314.pdfJim" } ]
2025-10-17T20:43:50.722657
6
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(-ucurrent-gold-2-amplifiers-question-)/
[ ucurrent gold 2 amplifiers question ] - Page 1
[ { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "May 24, 2014, 12:42:24 pm", "content": "Hi,I am implementing a current / voltage logger, whose design will be opensourced. The current monitoring part is similar to Dave's ucurrent golddesign. I read the initial article:http://alternatezone.com/electronics/ucurrent/uCurrentArticle.pdfThen, I read the new design here:http://www.eevblog.com/projects/ucurrent/In the new design, there are 2 amplifiers both with a gain of x10instead one with a gain of x100, as it was done in the previousdesign. Can anyone explain the reasons of doing so ?Thanks for helping !Texane." }, { "post_id": "", "author": "kizzap", "author_rank": "Unknown", "is_op": false, "timestamp": "May 24, 2014, 01:23:52 pm", "content": "He did a whole video on this..." }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "May 24, 2014, 01:37:36 pm", "content": "Missed this video, thanks !" } ]
2025-10-17T20:01:50.832501
3
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(-window-voltage-comparator-)/
[ window voltage comparator ] - Page 1
[ { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "October 17, 2009, 10:25:42 am", "content": "Hi,As a beginner, I am reading the following book: practical electronicsfor inventor, from Paul Scherz.For a light sensor project, I need a window voltage comparator. I useone from the above book. I attached the schema.What should happen:Vout is +5v when 2.3v<Vin<2.7vVout is 0v otherwise.However, I get the opposite...:Vout is 0v when 2.3v<Vin<2.7vVout is 5v otherwise.I use a lm339 quad comparator, so that I actually has only onecomparator. I tested the comparator inputs/outputs independentlyto see if it works, and I get right measures. Maybe there is somethingI didnot understand regarding the above schema...Any idea?Thanks for helping,Regards,Fabien." }, { "post_id": "", "author": "texane", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "October 17, 2009, 10:40:03 am", "content": "I think I misunderstood something... the schemaactually works as expected, sorry for posting" }, { "post_id": "", "author": "Simon", "author_rank": "Unknown", "is_op": false, "timestamp": "October 18, 2009, 08:41:46 pm", "content": "if you get a similar situation again (thats if it really happens) reverse the inputs on the comparators" } ]
2025-10-17T20:43:51.840836
3
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(3x-5y)dx-(xy)-dy-0/
(3x-5y)dx + (x+y) dy = 0 - Page 1
[ { "post_id": "", "author": "J4e8a16n", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "July 30, 2015, 04:18:57 pm", "content": "Hi,(3x-5y)dx + (x+y) dy = 0dy/dx = (5y-3x)/ (x+y)(5y-3x)/ (x+y) = 5A/ (x+y) - 3B/ (x+y)5y-3x = 5A - 3B5y-5A = 3x - 3B5(y-A) = 3(x-B)(y-A) * 5/3= x-B...............https://www.eevblog.com/forum/Smileys/default/huh.gifHave a good day,JPDaviau" }, { "post_id": "", "author": "German_EE", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 30, 2015, 06:51:33 pm", "content": "And the point of this math exercise is??" }, { "post_id": "", "author": "J4e8a16n", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "July 30, 2015, 10:18:10 pm", "content": "Is to find what type of solution exist for this equation.This is from Shepley L Ross 4th editionIntroduction to ordinary differential equations.It is not exact.I could not found an integrating factorI have tried v=y/x methodPartial fraction does not seem to workIt does not seem Bernouilli or homogenous.I am aiming to understand Laplace Transform.I do it for my pleasure and the pleasure to calculate my circuits.Maybe it is crasy but I am doing it for tree years now. I started with trigonometry. It is good for the mind.Well, that's it.JPDaviau" }, { "post_id": "", "author": "Mechatrommer", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 30, 2015, 10:29:14 pm", "content": "Quote from: German_EE on July 30, 2015, 06:51:33 pmwasting your time and mine... in one possibility... y=A, x=B..." }, { "post_id": "", "author": "onlooker", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "July 30, 2015, 11:26:19 pm", "content": "A thing having no purpose may still have solutions,(y-3x)2= C(y-x)" }, { "post_id": "", "author": "Christe4nM", "author_rank": "Unknown", "is_op": false, "timestamp": "July 31, 2015, 10:44:25 am", "content": "It's a differential equation. Write it in the form of dy/dx + y = x. Then solve like a first orderlineardifferential equation.Edit: tried to rewrite and solve it, but it's a non-linear differential equation. My abilities unfortunately only include linear ones with constant coefficients" }, { "post_id": "", "author": "Jope", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "July 31, 2015, 11:09:56 am", "content": "Solution by Wolfram Alpha:(3x-5y)dx + (x+y) dy = 0." }, { "post_id": "", "author": "IanB", "author_rank": "Super Contributor", "is_op": false, "timestamp": "August 01, 2015, 05:46:23 pm", "content": "Quote from: J4e8a16n on July 30, 2015, 10:18:10 pmAccording to Wolfram Alpha that method leads to a solution (i.e. let y(x) = x v(x) and proceed from there). However, the solution does not come out as anything simple." }, { "post_id": "", "author": "J4e8a16n", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "August 01, 2015, 09:38:05 pm", "content": "dy/dx = (5y-3x / x + y) / x = > -3 + 5y/x / 1+ y/xy/x = v y = vx ==>d y /dx = d vx/dx ==>v + v' x ==> v + x*dv/dx-----v + x* dv/dx = -3 + 5y/x / 1+ y/x ==>x dv/dx = -v^2+4v -3/ 1+vdx/x = 1+v / -v^2 +4v -3 dvfrom here complete the square?I am working at it)JPD" }, { "post_id": "", "author": "IanB", "author_rank": "Super Contributor", "is_op": false, "timestamp": "August 01, 2015, 10:22:11 pm", "content": "Something like this, I believe:" }, { "post_id": "", "author": "free_electron", "author_rank": "Super Contributor", "is_op": false, "timestamp": "August 01, 2015, 10:43:46 pm", "content": "Quote from: J4e8a16n on July 30, 2015, 10:18:10 pmi use this :" }, { "post_id": "", "author": "free_electron", "author_rank": "Super Contributor", "is_op": false, "timestamp": "August 01, 2015, 10:44:55 pm", "content": "Laplace Transformations are for beginners. Real men use a Widlar Transformations." }, { "post_id": "", "author": "J4e8a16n", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "August 01, 2015, 11:12:57 pm", "content": "Quote from: IanB on August 01, 2015, 10:22:11 pmYes." }, { "post_id": "", "author": "IanB", "author_rank": "Super Contributor", "is_op": false, "timestamp": "August 01, 2015, 11:14:33 pm", "content": "Quote from: J4e8a16n on August 01, 2015, 09:38:05 pmIt looks like you got it right up that point. You might notice that ( - v^2 + 4v - 3) can be factorized..." }, { "post_id": "", "author": "J4e8a16n", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "August 01, 2015, 11:18:04 pm", "content": "Thanks for your support)JPD" } ]
2025-10-17T19:36:21.847001
15
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(almost)-silent-micro-switches/
(almost) silent micro switches - what brands? - Page 1
[ { "post_id": "", "author": "arekm", "author_rank": "Unknown", "is_op": true, "timestamp": "November 09, 2013, 11:02:14 pm", "content": "Are there any brands of silent (or close to silent) micro switches? The typical ones are very loud and thus aren't good candidates for mouse-like equipment.Micro switch type I'm looking for" }, { "post_id": "", "author": "ConKbot", "author_rank": "Super Contributor", "is_op": false, "timestamp": "November 10, 2013, 12:12:46 am", "content": "Those are generally called \"Tatctile switches\" because they are (almost) silent, just mainly felt when you push the button. Almost any tactile switch you can get from farnell or ebay in that form factor would be near silentMicroswitches on the other hand are louder, though my mouse has microswitches instead of tactile switches, but it does make a nice audible click as you push the button." }, { "post_id": "", "author": "wraper", "author_rank": "Unknown", "is_op": false, "timestamp": "November 10, 2013, 12:29:03 am", "content": "Tact switches like on the picture are very bad idea for \"mouse like applicatoans\" as they work not so stable as should, have short life and overall feeling while pushing them won't be good. Only right choice is proper microswitches like thosehttp://www.ebay.com/itm/2Pcs-Micro-Switch-OMRON-D2FC-F-7N-10M-For-Mouse-New-/251336866229?pt=LH_DefaultDomain_0&hash=item3a84d839b5" }, { "post_id": "", "author": "arekm", "author_rank": "Unknown", "is_op": true, "timestamp": "November 10, 2013, 08:24:09 am", "content": "It needs to be the same type as shown on the photo, so that omron won't fit.Googling for tactile switches then -- found Omron B3F-1002" }, { "post_id": "", "author": "G7PSK", "author_rank": "Super Contributor", "is_op": false, "timestamp": "November 10, 2013, 09:28:08 am", "content": "My Hama twister mouse has just died as well due to the use of tact switches but as it was 7 years old I wont hold a grudge against it, the tact switches were not of the usual type either so I could not find replacements. Just ordered anothe wireless mouse meanwhile I have to put up with a rat that I keep just in case." }, { "post_id": "", "author": "SeanB", "author_rank": "Super Contributor", "is_op": false, "timestamp": "November 10, 2013, 10:02:56 am", "content": "Grab those out of an old cheap mouse, you will probably find one that has the right switches if you look through a pile of them in a ewaste pile." }, { "post_id": "", "author": "wraper", "author_rank": "Unknown", "is_op": false, "timestamp": "November 10, 2013, 02:45:30 pm", "content": "Quote from: arekm on November 10, 2013, 08:24:09 amI have some B3F-1050 which are same as B3F-1000 just taller. Seem to be quieter that average. And they are with lowest operating force (0,98N) in B3F series. B3F-1002 is 1.47N however. Take in account that lower force switches have longer life than high force ones. B3F-1000 has 1 000 000 operations durability, while B3F-1002 only 300 000" }, { "post_id": "", "author": "Stonent", "author_rank": "Super Contributor", "is_op": false, "timestamp": "November 11, 2013, 03:55:27 am", "content": "I prefer the click. But that's just me. I used to use a Model M keyboard for a little while at one job. I loved it." }, { "post_id": "", "author": "Tube_Dude", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "November 12, 2013, 05:32:02 am", "content": "Anyone knows where I can find this type of switch, but normaly closed. Means, it opens when pressed." } ]
2025-10-17T20:13:19.920849
9
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(almost)-zero-miliamps-on-the-power-supply-display-with-no-load-connected/
(Almost) zero miliamps on the power supply display with no load connected - Page 1
[ { "post_id": "", "author": "bodzio_stawski", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 01, 2024, 11:39:04 am", "content": "Hi!I have recently been wondering about the methodology of measuring current in power supplies, which shows the current drawn from them with an accuracy of 1 mA. (I have one similar to the one below).https://www.amazon.com/Adjustable-Switching-Regulated-Interface-Adjustments/dp/B09XTWKVLD/ref=sr_1_21?crid=UBUETUWMHPLS&keywords=bench+power+supply+5A&qid=1706787155&sprefix=bench+power+supply+5a%2Caps%2C205&sr=8-21I noticed that when I do not connect any load to this power supply, after pressing OUTPUT it should simply display 0.000A, but it displays once 0.000A and once 0.005A. When I connect a resistor to the power supply outputs, 5mA is always added to the current measured by the power supply.So, for example, when I connect a 1kohm resistor and set it to 5V, I see 0.010A instead of 0.005A, etc.Is this behavior of the power supply normal or some hidden fault?" }, { "post_id": "", "author": "inse", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 01, 2024, 12:07:59 pm", "content": "Don’t confuse accuracy with resolution" }, { "post_id": "", "author": "bodzio_stawski", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 01, 2024, 12:13:40 pm", "content": "Perhaps this was the impression, but the very fact of the existence of non-zero current despite the lack of load connection worried me." }, { "post_id": "", "author": "inse", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 01, 2024, 12:17:10 pm", "content": "Perhaps there is some kind of discharge resistor across the output clamps" }, { "post_id": "", "author": "Buriedcode", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 01, 2024, 12:19:06 pm", "content": "Quote from: bodzio_stawski on February 01, 2024, 12:13:40 pmYou mean non-zerodisplayedcurrent. You are assuming the power supply (and the display) is measuring the output current perfectly - it isn't. There will be errors, including offsets, which in this case appears to be around 2.5mA - and if the resolution of the measurement is 5mA, then it will toggle between the two nearest values - 0.000 and 0.005.If it always adds 5mA to the diplsay, then the offset iwth +5mA, or + 0.005A. Some instruments allow calibration against a known reference, so you can zero these offsets out." }, { "post_id": "", "author": "bodzio_stawski", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 01, 2024, 12:39:23 pm", "content": "The port can show 0.005, 0.006, 0.007 depending on the load, so it's not about resolution. To make matters worse, what is displayed depends on the voltage set. At 5V the current still fluctuates between 0 and 0.005A, while at e.g. 20V it is permanently 0.005A. However, when you wait a few minutes or more, the value fluctuates between 0.005 and 0.000, pointing often to 0.000, and finally stops at 0.000. PolskiBut when you then turn the power off and on again, those few milliamps will show up on the display again without any load connected.Unfortunately, it is not possible to calibrate the power supply (at least without intervening inside the device)." }, { "post_id": "", "author": "Terry Bites", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 01, 2024, 01:48:03 pm", "content": "1% accuracy is hard to achieve with the best off the shelf parts. You'll see boasty specs for precision current sense amplifiers. That's all well and good but the typical external shunt resistor will add a nasty temcpco of 0.39%/'C. If you go from +25 to +50 you'll expeience 10% drift, ouch.There are devices with integrated shunts with a much better tempco they tend to be aimed at high current measurement. eg The INA250 looks like good choice for lower currents. One day I'll read the datasheet." }, { "post_id": "", "author": "bodzio_stawski", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 01, 2024, 02:14:41 pm", "content": "Quote from: Terry Bites on February 01, 2024, 01:48:03 pmWell, it's true, I don't expect super accuracy from a somewhat unknown device. However, I am curious how the power supply's own ammeter can measure any self-current when there is no load. I wonder what is a source of that effect on display. I admit that I approached this matter somewhat in the way that the \"lack of an electrical quantity\" cannot generate any value error. Do other brands of laboratory power supplies have similar currents?" }, { "post_id": "", "author": "BeBuLamar", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 01, 2024, 02:31:04 pm", "content": "The specs said that current display accuracy is +/- 0.5% +5 digit. The fact that it has the +5 digit if it displays 5 cound more or less it's in specs. You shouldn't expect too much accuracy." }, { "post_id": "", "author": "Manul", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 01, 2024, 04:21:23 pm", "content": "Quote from: bodzio_stawski on February 01, 2024, 02:14:41 pmCurrent is usually measured by using a shunt, aka current sense resistor. When current flows, there is a voltage drop. That voltage is what is measured. Lab power supply must be able to measure ralatively big range of current, from milliamps to amps. The sense resistor must be low value, to not heat up too much at high currents. Lets say it is 50 milliohms. But then low currents are difficult to measure. At 1mA you get voltage drop of only 50 microvolts! You ask, how can anything at all come out of nothing at zero current? We are dealing here with very low voltages, we need amplifier. Any amplifier will have offset and gain errors. Plus there could be other issues, like ground potential shifts in the circuit board. Current sense resistor is usually measured by using differential amplifier and ground shifts should not affect measurement - theoretically. But the measured voltage likely does not go as differential signal all the way to ADC, so ground shifts might still affect it. And yes, there are ADC errors too. There is also noise. Long story short, it is not easy to achieve microvolt precision. When there is no signal present, what is still present are errors and noise, there is no way to fully avoid that." }, { "post_id": "", "author": "MarkT", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "February 01, 2024, 08:11:50 pm", "content": "Suspect they just fake any reading below 0.005 to 0 to hide the offset error (which would be more annoying in most situations)." }, { "post_id": "", "author": "bdunham7", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 01, 2024, 08:24:03 pm", "content": "Quote from: bodzio_stawski on February 01, 2024, 02:14:41 pmThere are scaling errors, linearity errors and nulling (zero) errors. They all have their various causes, but there's nothing unusual in having some noise or fluctuations at the zero point any more than there would be having the same noise or fluctuations at some other point. Its a universal issue with almost all types of meters. It's not the \"electrical quantity\" or lack thereof, it's the meter itself that generates the error." }, { "post_id": "", "author": "SiliconWizard", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 01, 2024, 08:30:57 pm", "content": "From your description, the current reading would appear to have 5mA resolution, so what you see is, unfortunately, normal. Yes, say the current measurement is done with a 10-bit resolution, if say the current range is up to 5A, there that's your about 5mA resolution. Nothing you can do about it, and not a sign of defect as long as it was documented in the power supply's specs. But don't expect neither good resolution nor good accuracy with these power supplies. The reading is just meant to give you a rough idea. If you need better, use a multimeter." } ]
2025-10-17T16:41:19.997882
13
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(analog-electronics)-capacitor-measurement-circuit/
[Analog Electronics] Capacitor Measurement circuit - Page 1
[ { "post_id": "", "author": "Belquay Neust", "author_rank": "Newbie", "is_op": true, "timestamp": "March 04, 2020, 12:50:56 pm", "content": "Hello!I want to build a circuit that can measure a capacitor. In that case I have used a REF102 and LM358 as (as much as it possible) precision current source. I want to measure between for example 1nF to 10uF. I want to make it as simple as it possible, and for now I want to receive a linear load voltage on capacitor, but I am receiving a exponential slope with a knee over 63%. What can I do to make it more linear?" }, { "post_id": "", "author": "fcb", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 04, 2020, 01:36:00 pm", "content": "If you charge/discharge a capacitor with a constant current you will get a constant slope ramp. So I'm assuming you are measuring the time to go between two voltages?What voltage is V+? Which voltage does the 63% relate to?" }, { "post_id": "", "author": "Wimberleytech", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 04, 2020, 01:44:00 pm", "content": "Quote from: Belquay Neust on March 04, 2020, 12:50:56 pmWhat are you using for V+ of the REF102?As the capacitor charges up, you are probably losing headroom for the REF102, so it is no longer regulating." }, { "post_id": "", "author": "Belquay Neust", "author_rank": "Newbie", "is_op": true, "timestamp": "March 04, 2020, 02:29:03 pm", "content": "You are talking about Quiescent Current, but I am talking about current from OP AMP, that I have in my circuit. From this datasheet is completely possible to make 1uA current source, but I can't get a constant slope ramp with about 8uA from LM358.On REF102 I have +5V.It is reacting like I would connect a capacitor to 500k resistor and 10V. Or maybe someone have a hint how should I build a stable current source for capacitor measurement if I am wrong with REF102?" }, { "post_id": "", "author": "Wimberleytech", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 04, 2020, 02:36:08 pm", "content": "Quote from: Belquay Neust on March 04, 2020, 02:29:03 pmAt T=0, 5 volts on pin 2, 0 volts on pin 4, 10 volts on pin 6? Nope" }, { "post_id": "", "author": "rstofer", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 04, 2020, 02:48:19 pm", "content": "Analog computers make a stable slope all the time, it's all part of that integration thing.Consider an op amp configured with dual 15V supplies (for now), a 1 ufd capacitor in the feedback path instead of a gain resistor and a 1 Mohm resistor to the inverting input. Ground the non-inverting input.Start with the input to the 1 Mohm resistor equal to 0V. Now set the input voltage to +10V. Exactly 1 second later, the op amp output will be -10V and the ramp down will have been linear. That's because Tau (=R*C) is 1 second (10-6Farads * 10+6Ohms => Tau = 1 second)https://www.electronics-tutorials.ws/opamp/opamp_6.htmlThere are other ways to make a linear capacitor charge circuit but this is the one I am familiar with. I like analog computing!You don't need a linear charge voltage, all you need to do is change the voltage (as a % of operating voltage) over some period of time and then fit the time and voltages into the charge equation.Vout= Vin* (1-e-t/Tau) + V0So, the initial voltage goes into V0and is usually 0V, Tau is what you're trying to determine because you get Tau = R*C and you know R. Vin, Vout and t. A little ugly arithmetic and you're there.https://www.picotech.com/library/experiment/capacitorYou know that in 1 Tau seconds, the capacitor will charge to 63% of the input voltage, starting from zero. Substitute t = Tau in the equation above and you get Vout= Vin* (1-e-1) + V0with V0= 0. This results in 0.632 or 63.2% of the input voltage in 1 time constant.I have attached a charge plot where I am hitting the capacitor with a square wave.The Internet is full of capacitor measuring projects, try Google." }, { "post_id": "", "author": "fcb", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 04, 2020, 02:48:46 pm", "content": "REF102 minimum voltage is 11.4V, with your design you'll need at least 15V." }, { "post_id": "", "author": "Wimberleytech", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 04, 2020, 05:17:28 pm", "content": "I have built a capacitor tester using the method described by rstofer. I used an arduino. It worked well.I can understand the desire to use a constant current even though it is not necessary." }, { "post_id": "", "author": "rstofer", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 04, 2020, 06:38:58 pm", "content": "Quote from: Wimberleytech on March 04, 2020, 05:17:28 pmUsing an Arduino allows for automated selection of charging resistors.Here is the Digilent Impedance Analyzer for the Analog Discovery 2 (a very cool gadget)https://store.digilentinc.com/impedance-analyzer-for-analog-discovery/If you skip down the page, on the right, there is a link to the schematic and you can see where relays are used to select decade values of resistors (upper right of schematic).https://reference.digilentinc.com/_media/reference/instrumentation/analog_discovery_impedance_analyzer_sch.pdfBy using small relays, they get away from the issues related to driving MOSFETs as well as having to account for voltage drop across the MOSFET. Pretty clever!I could see doing something similar with an Arduino but like everything else related to Arduino applications, it has already been done and the project is on the Internet:https://www.arduino.cc/en/Tutorial/CapacitanceMeterGoogle for 'Arduino capacitor tester' without the quotes" }, { "post_id": "", "author": "Wimberleytech", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 04, 2020, 06:58:52 pm", "content": "Quote from: rstofer on March 04, 2020, 06:38:58 pmThat is what I did. Two values. Should have been more to handle a wider range of caps. This effort was a teaching exercise. I gave the problem to a kid I was teaching electronics and programming. Every exercise I gave him, I had to solve myself.When switching resistors, I set one (port) as output and tristated the others. Lived with whatever VDS there was associated with the output drivers.This was a great project for the kid because lots of different things can be learned." }, { "post_id": "", "author": "Belquay Neust", "author_rank": "Newbie", "is_op": true, "timestamp": "March 06, 2020, 08:55:54 am", "content": "Ok, I have changed my voltage to +15V and -5V. I've got a little better results, but still it's impossible to measure 10nF. I do not want to use arduino, because my project is on STM32F103VC, but I don't want to fixing measurement in firmware, because I do not believe that resolution of ADC should work correctly. Now I have:for 10nFfor 2uF" }, { "post_id": "", "author": "Zero999", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 06, 2020, 11:35:06 am", "content": "If you want to measure the capacitance, there are easier ways to do it. How about a simple Schmitt trigger oscillator? The output frequency is inversely proportional to the capacitance. Use a low a comparator with a push-pull output stage, such as the MCP6561 or TLC3702 to make life easier.If the correct values of R1, R2 & R4 are selected, then F = 1/(RC), to within 1% and even rounding R4 to 150k will give a closer tolerance, than most capacitors." }, { "post_id": "", "author": "fcb", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 06, 2020, 12:20:52 pm", "content": "Quote from: Belquay Neust on March 06, 2020, 08:55:54 amIf you are using the diagram in post#1 with V+ now +15V, you will only get a reliable reading up to 15-11.4V=3.6V or thereabouts. Read the REF102 datasheet.Probably wise to post more details about the exact setup you are using, ADC sample rate, desired accuracy, schematic etc.." }, { "post_id": "", "author": "Belquay Neust", "author_rank": "Newbie", "is_op": true, "timestamp": "March 06, 2020, 02:12:55 pm", "content": "I have solved my problem by Instrumentation AMP, no Arduino and no comparators. On my output i have 7.8 uA and linear response. Now I can easily calculate this by firmware. Ok, now I will go on. Thanks for your good faith and fast reaction." }, { "post_id": "", "author": "Wimberleytech", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 06, 2020, 02:17:11 pm", "content": "Quote from: Belquay Neust on March 06, 2020, 08:55:54 amYou are still not giving enough headroom to the REF block. I think you need to change your architecture.Maybe something like this. Get a matched pair for the PNPs but you can test the concept with discretes." }, { "post_id": "", "author": "fcb", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 06, 2020, 04:23:58 pm", "content": "Quote from: Belquay Neust on March 06, 2020, 02:12:55 pmI still don't think you are understanding the limitation with the REF102 V+ rail.All you've done is added a $5 amplfier with a gain of 3.Apart from the gain of 3, this really gives you nothing extra over the reading the OUT on the LM358." }, { "post_id": "", "author": "Zero999", "author_rank": "Super Contributor", "is_op": false, "timestamp": "March 08, 2020, 07:07:19 pm", "content": "Quote from: fcb on March 06, 2020, 04:23:58 pmYes, the same result can be achieved by using the other half of the LM358, as a non-inverting amplifier with a gain of 3." } ]
2025-10-17T17:54:25.509098
17
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(another)-isolation-question/
(Another?) Isolation question.... - Page 1
[ { "post_id": "", "author": "MartolFart", "author_rank": "Newbie", "is_op": true, "timestamp": "July 08, 2020, 04:25:06 pm", "content": "Hi,I have a USB scope I've been using for SMPS troubleshooting from a desktop PC.... I'm switching (no pun!) to using a laptop and was planning to run from battery to facilitate probing across front end components which I'm thinking is safe (assuming normal HV precautions). But were I to accidentally leave the laptop connected to the charger, I'm thinking it would not be an issue either? The charging adapter plug in is not polarized with no ground prong. There is no continuity from prongs to tip connectors. Thoughts? Thanks!" }, { "post_id": "", "author": "Benta", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 08, 2020, 05:43:03 pm", "content": "Yes. You'll end up killing yourself.Donotisolate the test equipment,isolate the device under test(DUT).This means: get hold of a mains isolation transformer." }, { "post_id": "", "author": "Ian.M", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 08, 2020, 05:58:13 pm", "content": "This comes under the general category of 'Floating a Scope not designed or intended for floating use'. Good engineers have been killed doing that - it only takes ONE small mistake to electrocute you. Differential HV probes rated for CAT II usage aren't *that* expensive nowadays so there should be no need, or excuse, for floating a scope.The *ONLY* way I'd ever consider floating a laptop is if it (and all connected instrument pods etc.) are *TOTALLY* inaccessible behind a perspex safety screen, its on battery power with no PSU connected, any need for the user to control it is handled with awirelesskeyboard and/or mouse, and probes are only connected/disconnected from the D.U.T. with its mains power disconnected and its reservoir capacitor discharged (i.e. absolutely *NO* hand-held probing).Don't trust the 'isolation' provided by a non-grounded laptop PSU. It will have a relatively high capacitance between input and output, and may well suffer insulation breakdown if stressed by high frequency high voltage switching waveforms as are common in SMPSes, power inverters, VFDs etc." }, { "post_id": "", "author": "David Hess", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 08, 2020, 07:34:27 pm", "content": "Quote from: MartolFart on July 08, 2020, 04:25:06 pmInternally the charger has a transformer which provides galvanic isolation between the input and output. However it was designed for and operates with a minimum common mode input to output voltage and they are typically only rated for continuous operation to a fraction of their input voltage between the primary and secondary.In theory if you want to do this, then an isolation transformer would allow it however as others have already said, this is a hazardous mode of operation and is not recommended." }, { "post_id": "", "author": "Purduephotog", "author_rank": "Regular Contributor", "is_op": false, "timestamp": "July 09, 2020, 02:24:10 am", "content": "I was working under a desk in Germany at an AFB. They run on 220. Well... someone dropped a neutral- so I took 110V or 220V across the chest... by touching the USB port on one computer and the Serial port on another computer.So don't float it. It hurts....there was a MASSIVE writeup over the incident, as you'd expect. That could very well have killed me given where and when I was working." }, { "post_id": "", "author": "magic", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 09, 2020, 07:06:43 am", "content": "Quote from: MartolFart on July 08, 2020, 04:25:06 pmYes, the problem is that when you connect unisolated test equipment to an HV circuit, all normal HV precautions also apply to the test equipment now.And if you further have a laptop connected to that scope, ..." }, { "post_id": "", "author": "Benta", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 09, 2020, 10:47:49 am", "content": "Quote from: blueskull on July 09, 2020, 07:20:30 amIf the scope is correctly earthed (as it should be), the GFCI will work perfectly." }, { "post_id": "", "author": "capt bullshot", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 09, 2020, 10:59:00 am", "content": "Apart from the plentyfully mentioned personal safety issues, measuring live SMPS components the way you mentioned might disturb or damage your equipment due to high frequency and high voltage common mode signals. Better do not measure switching nodes or nodes significantly affected by the primary switching action with any kind of floated scope, except it is specially made for this purpose (e.g. the TPS20xx, or some of the stuff from Cleverscopes). If not for your personal safety, for the sake of your equipment." }, { "post_id": "", "author": "Benta", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 09, 2020, 04:27:04 pm", "content": "Quote from: blueskull on July 09, 2020, 11:03:14 amWhether you simultaneously touch L and N on the \"live\" side or the \"floated\" side of the isolation transformer makes no difference, neither will trigger the GFCI and you'll be just as dead.The point is that having 'scope/laptop at live potential is lethal, having them at earth potential is safe (apart from the fact that you're working with 230 VAC, of course)." }, { "post_id": "", "author": "Ian.M", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 09, 2020, 05:34:04 pm", "content": "Anyone who doesn't believe that an isolating transformer prevents GFCI (RCD) protection devices from working should consider the following facts:GFCIs detect faults by detecting current imbalance between Line and Neutral.Neglecting capacitive leakage and non-ideal insulation, by Kirchoff's current law, the current entering any two terminal transformer winding at one terminal must be identical to that leaving it at the other (as any point in the winding may be considered a KCL node).Capacitive leakage in a line frequency mains transformer will be far less than even the most sensitive GFCI's trip threshold current.Therefore it is impossible for a GFCI with either its supply or load terminals directly and only connected to a two terminal transformer winding to trip, unless the circuit insulation or transformer insulation is defective.To add ground fault detection after an isolating transformer with a floating secondary would require sensing the ground conductor current of all test equipment that may introduce a ground to the D.U.T. and wouldn't protect you if you made contact with a live part of the D.U.T and a grounded test equipment chassis on the load side of the ground current sensing point. It would also be defeated if anything introduced a parallel ground path that did not pass through the ground current sensor. Unfortunately ground conductor current sensing circuit breakers are no longer readily available." }, { "post_id": "", "author": "calzap", "author_rank": "Frequent Contributor", "is_op": false, "timestamp": "July 09, 2020, 06:37:36 pm", "content": "If you are touching the scope probe or attaching the ground clip to an non-isolated DUT, there is the chance than any piece of metal on the computer (case, latch, hinges, connectors, etc.) and anything attached to it might be hot relative to ground or a neutral. Say it's the hinges. If you are grounded and touch them, it could be the last thing you touch.It you are using an isolation transformer for the DUT, use a multimeter to check that it's really isolated before proceeding with tests. Some transformers that are sold with an isolation label are not really isolated from ground. They are designed to protect equipment from line noise and surges. Read the fine print; use a multimeter to check.Mike in California" }, { "post_id": "", "author": "MartolFart", "author_rank": "Newbie", "is_op": true, "timestamp": "July 17, 2020, 07:20:49 am", "content": "Thanks to everyone for their comments, concerns and recommendations! Back at it after some domestic distractions!In summary, ideally I'd have the isolation auto transformer and purpose built differential probe.... When I was in production doing this kind of work frequently I would already have or track down these goodies (usually). But us old dabblers just wanna have some fun without expending a ton of funds! I did take a look at differential probes and didn't see much under $200 (and none too impressive really), maybe I'm missing the deals to be found? Pretty sure I don't need the 10kV 10GHz jobs....So anyway, I'm doing the two 100x probe (ground leads removed) A-B approach, and based on the sage advice rendered, won't (intentionally) test with the laptop on its charger.Another idea I had for isolation work around is to use a disconnected from mains UPS to power the DUT for quick tests (under light load and using the light bulb current limiting gimmick)?Btw I am definitely an adherent of the one hand behind my back HV testing technique (if I can't just hang a probe somehow) and I don't do it enough to get complacent (which is probably the biggest risk right along with faulty design and implementation issues) which is how I've earned my moniker I imagine! I should be okay unless I fall off a ladder...." }, { "post_id": "", "author": "magic", "author_rank": "Super Contributor", "is_op": false, "timestamp": "July 17, 2020, 08:31:19 am", "content": "If you use standard passive probes without ground leads then you can ground the scope without issues.Moreover, you probably should, in case one of the probes arbitrarily decides to short out. If the scope is grounded, there will be a bang, smoke and tripped circuit breaker. If it's floating, there will be a surprise HV on the scope.editHonestly, I were to float a scope I would rather connect it to the hot ground, which is the only point of reference that I have ever cared about in an SMPS. That way at least Iknowthe scope is live, stand back and don't touch it. Not sure if you should be doing it, though, given the sort of questions you askQuote from: MartolFart on July 17, 2020, 07:20:49 amNo such thing, it's either auto or isolation." }, { "post_id": "", "author": "TimFox", "author_rank": "Super Contributor", "is_op": false, "timestamp": "September 05, 2020, 10:31:57 pm", "content": "A related thing to watch out for:If you have a metal-cased computer (or other equipment), and the PE (3rd prong) wire is not connected properly, then the two capacitors in the line filter will pull the metal case to half of the mains voltage, in series with a reasonable but not trivial capacitance. The capacitor should be chosen such that 60 V or 110 V (depending on the local mains) should not electrocute a healthy person, but you can easily receive a jolt that could knock you off a ladder or other slapstick cause of injury, especially in 220 V lands. At work, we called this the \"Dan effect\", as in \"it's not easy to shock Dan, but...\" after he encountered this phenomenon in the field, where the locals had not bothered to ground the generator properly." }, { "post_id": "", "author": "bdunham7", "author_rank": "Super Contributor", "is_op": false, "timestamp": "September 05, 2020, 11:16:10 pm", "content": "Quote from: MartolFart on July 08, 2020, 04:25:06 pmIs your USB scope rated for those voltages and CAT II?As for relying on your charging adapter for ground isolation, it may be adequate to keep 120VAC 60HZ at bay, but depending on how you connect everything up, you could be exposing it to something like 400V and 50kHz. It won't do well at that. And even before it goes up in smoke, you may have a highly energized laptop. Make sure your files are backed up and your will is current." }, { "post_id": "", "author": "bdunham7", "author_rank": "Super Contributor", "is_op": false, "timestamp": "September 05, 2020, 11:18:36 pm", "content": "Quote from: magic on July 17, 2020, 08:31:19 amHe's referring to a combination unit with both in one box, typically autotransformer first and isolation transformer second." }, { "post_id": "", "author": "MartolFart", "author_rank": "Newbie", "is_op": true, "timestamp": "September 06, 2020, 11:33:44 pm", "content": "Thanks for the comments!My pure chinesium USB scope has no stinking IEC 1010 category labeling... It does proudly sport the CE insignia (self tested to the highest standards!). The max input with 1x probe is 35V. The 100X probes don't have cat specs either, just 2KV DC+AC again with CE label.Per my previous post, I'd already discarded the idea of leaving the charger on the laptop powering the USB scopage gizmo; may as well just run off the battery anyway. I really don't think it was a ridiculously stupid question or idea though.... I didn't see any responses to the other idea of running the DUT off a disconnected from mains UPS? As I mentioned before, if I was doing this kind of work frequently/for a living, I'd prolly break down and buy an isolation transformer, maybe even a fancy one with integrated rheostat...So another question comes to mind as a result of the test eq cat rating.... If the DUT is powered by \"protected electronic equipment\", does CAT I suffice?My reading on the IEC category ratings indicated these were developed to address transient and available energy (essentially short circuit current) as adjunct to the insulation voltage ratings already commonly specified..... My ancient Fluke DMM has no labelling on the leads with max 1000VDC/750AC on the input jack and certainly no CAT rating!Not having much luck with the SMPS PD so far (I did fix two other smaller ones!), I might have to beg some help when I get data collected, trying to sketch out the discrete chopper schematic is killing my old eyes....)!" }, { "post_id": "", "author": "magic", "author_rank": "Super Contributor", "is_op": false, "timestamp": "September 08, 2020, 05:19:20 am", "content": "Quote from: TimFox on September 05, 2020, 10:31:57 pmI will add yet another: 3 phase motors with the chassis miswired to line" } ]
2025-10-17T17:42:53.315625
18
electronics
beginners
true
https://www.eevblog.com/forum/beginners/(another)-pulse-generator-with-si5351/
(another) Pulse generator with Si5351 - Page 1
[ { "post_id": "", "author": "stcoso", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 20, 2020, 11:03:09 am", "content": "Hi! I'm trying to design a pulse generator.I need adjustable 1-10 ns pulse with adjustable frequency (ideally 10kHz/50MHz).Si5351 has 3/8 clock outputs with adjustable 333ps/step phase offset. So I'm thinking to generate 2 clock signal ( same frequency but out of phase) and feed them into a fast comparator (with reasonable rise/fall) to obtain the pulse that I need.Where am I wrong?" }, { "post_id": "", "author": "radiolistener", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 20, 2020, 03:25:33 pm", "content": "si5351 already has 1 ns rise/fall time. So, there is no need for comparator, you can use it's output directly." }, { "post_id": "", "author": "stcoso", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 20, 2020, 03:31:50 pm", "content": "Ok... but it's 1ns 20/80% and that wouldn't allow 1ns pulse width" }, { "post_id": "", "author": "radiolistener", "author_rank": "Super Contributor", "is_op": false, "timestamp": "February 21, 2020, 09:43:50 am", "content": "Quote from: stcoso on February 20, 2020, 03:31:50 pm1 ns pulse width is 500 MHz. But you're mention that you're needs 10kHz...50MHz frequency with 1..10 ns rise time. si5351 allows to produce 5 kHz...200 MHz with rise time 1 ns. Which ideally fits your requirements, isn't it?" }, { "post_id": "", "author": "stcoso", "author_rank": "Regular Contributor", "is_op": true, "timestamp": "February 21, 2020, 12:18:41 pm", "content": "1 to 10 ns pulse width. Rise/fall need to be good enough to get 1ns pulse with decent shape (this signal will be fed into a gan driver). For a 1-ns pulse width 1ns rise/fall time are clearly not enough. Also, si5351 has fixed duty cycle and is limited to 200MHz so can't use this directly to generate 1ns pulse width.I'm wondering if there is a clever way to achieve what I need.I could also use a AND gate with the clock signals from the si5351 shifted (starting from 180Β°) to achieve overlap." } ]
2025-10-17T17:55:17.257498
5
electronics
beginners
true
End of preview. Expand in Data Studio

πŸ› οΈ EEVblog Forum Dataset: The Electronics Mentor

Stop training on synthetic data. Train on real engineering wisdom. 200K+ authentic technical conversations where beginners learn from seasoned engineers, troubleshooting experts guide newcomers, and practical wisdom gets passed down through generations of makers.

πŸš€ What Makes This Special?

This isn't just another Q&A dataset. This is 200,756 posts of authentic mentor-apprentice dialogue where beginners learn from seasoned engineers, troubleshooting experts guide newcomers, and practical wisdom gets passed down.

πŸ“Š Dataset at a Glance

Metric Value Why It Matters
Total Conversations ~20,000 threads Rich context across entire problem-solving journeys
Expertise Hierarchy 5 contributor ranks Train AI to match response style to user's level
Time Span 2009-2025 16 years of evolving engineering knowledge
Domains Covered 15+ subfields From RF design to beginner fundamentals

🎯 Perfect For Building...

πŸ€– The Ultimate Electronics Mentor

# Your AI after training on this data:
User: "Should I buy a $200 Korad or used Tektronix power supply?"
AI: "For beginners, start with the Korad - reliable out of the box. Once you're comfortable, explore used professional gear. Here's what to look for..."

πŸ”§ Intelligent Troubleshooting Assistants

  • Diagnose circuit problems with expert reasoning patterns
  • Guide users through systematic debugging workflows
  • Explain technical concepts at appropriate complexity levels

πŸŽ“ Adaptive Learning Companions

  • Scale explanations from beginner to advanced
  • Provide practical project guidance
  • Teach electronics through real-world examples

πŸ—οΈ Technical Deep Dive

Data Structure That Tells a Story

Each thread is a complete learning journey:

{
  "thread_title": "Help with Amplifier Repair",
  "posts": [
    {
      "author": "CircuitNewbie",
      "author_rank": "Newbie",        // πŸ‘Ά Learning level
      "content": "My amplifier has distortion..." 
    },
    {
      "author": "OldSchoolEngineer", 
      "author_rank": "Super Contributor", // πŸŽ“ Expert level
      "content": "Start by measuring bias currents..."  // πŸ’‘ Wisdom
    }
  ],
  "domain": "repair",
  "subdomain": "amplifiers"
}

Domain Coverage

Category Examples Training Value
Beginner Fundamentals Ohm's Law, basic circuits Patient explanation styles
Advanced Design RF, microwave, PCB layout Expert-level reasoning
Troubleshooting Repair, diagnostics Systematic problem-solving
Tool Mastery Test gear, instrumentation Equipment selection logic

πŸš€ Getting Started in 60 Seconds

from datasets import load_dataset

dataset = load_dataset("nick007x/eevblog-forum-data")

# Extract expert mentoring patterns
def find_teaching_moments(thread):
    if any(post["author_rank"] in ["Super Contributor", "Frequent Contributor"] 
           for post in thread["posts"]):
        return {
            "student_question": thread["posts"][0]["content"],
            "expert_guidance": [p for p in thread["posts"] 
                              if p["author_rank"] in expert_ranks]
        }

mentoring_data = [find_teaching_moments(thread) for thread in dataset]

πŸ’‘ Pro Training Strategies

1. Expert-Apprentice Pairs

# Train AI to respond like seasoned engineers
training_pairs = []
for thread in dataset:
    if thread["post_count"] > 2:
        training_pairs.append({
            "instruction": thread["posts"][0]["content"],
            "response": expert_reply(thread)  # Highest-ranked contributor
        })

2. Progressive Difficulty Training

# Match explanation complexity to user level
def adaptive_learning(thread):
    user_level = thread["posts"][0]["author_rank"]
    expert_replies = [p for p in thread["posts"][1:] 
                     if p["author_rank"] != "Newbie"]
    
    return {
        "user_level": user_level,
        "appropriate_responses": expert_replies
    }

🌟 Real-World Impact

Companies are using this data to build:

  • Electronics design copilots that understand engineering trade-offs
  • Technical support bots that actually solve hardware problems
  • Educational platforms that adapt to student skill levels
  • Equipment recommendation engines with practical wisdom

πŸ› οΈ Sample Use Cases

# Build a power supply selection assistant
def recommend_power_supply(budget, experience, needs):
    # Your model trained on 1,000+ real equipment discussions
    return {
        "recommendation": "Korad KA3005D for beginners",
        "reasoning": "Reliable, accurate, and minimal maintenance",
        "alternatives": ["Used HP if you're comfortable with repairs"],
        "warnings": ["Watch for obsolete ICs in vintage gear"]
    }

🀝 Community & Contribution

Join engineers and AI researchers already using this dataset to:

  • Create open-source electronics tutors
  • Benchmark technical reasoning in LLMs
  • Develop next-generation engineering assistants

Ready to train AI that doesn't just answerβ€”but teaches?


"The best way to learn is from experience. The second best is learning from someone else's experience. This dataset gives you both."

⭐ Like this dataset if you're building the future of technical education!

License: MIT | Original Source: EEVblog Forum | Curated for AI Training

Downloads last month
26