Is a $7 LCR Meter / Component Tester from Ebay any good?
Dave tests the M328 (LCR-T4) model component tester.
HUGE Forum Thread:
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/
Forum summary videos here: https://www.youtube.com/watch?v=on1ZrWNt2Us
This group seems to maintain a version of the firmware:
https://www.mikrocontroller.net/articles/AVR_Transistortester
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Hi. This is going to be a follow-up video to my previous mailbag one where right at the end of the mailbag, somebody sent in this thing which looked like just some no-name generic tester aboard from ebay. They were like no instructions, no nothing. There's no labeling on it, you know.

and it just like what the hell was this thing and I just sort of, you know, brush to the side and quite rightly I copped a lot of flack for this so yep, sorry I should have at least put it through its paces. So here we go. We're going to take a look at one of these. $7.00 I you can might even be able to get it slightly cheaper $7.00 Delivered LCR meter slash transistor tester slash component analyzer slash whatever you want to call this thing now.

I Always aware that these kind of things existed, but I hadn't hadn't been following the 156 page eevblog forum thread on this. that's not post that's pages, so please forgive me that. I'm not going to go back and read the entire hundred and fifty-six page thread about these things now. this particular one, I've found it on eBay and it's the Emma three to eight but it goes under various different names and it calls itself your parent up calls itself the Emmet tester like there's no other like information on here and that's one of the things like I know it's only seven bucks, but is it too hard to actually you know silkscreen on there what this thing actually does or something like that I don't know it would have been handy.

Anyway, let's get into. apparently it's a component tester and apparently it's pretty good. These have a big following, lots of fanboys out there and people wanted me to test it out, so let's give it a go. This is this particular.

M Three to Eight one and yes, I do have a brand new battery because if you noticed in the mail bag, if I use one that had a much lower voltage which by the way does not show up like a seven point something volts. There you go. The contrast is just unreadable on this thing even though it doesn't give you a low battery warning error message. So there's the first problem with this thing now.

I Know that there are dozens and dozens of variations on this thing, if not hundreds of variations on this thing. People put them in their own do-it-yourself housings and all sorts of stuff. I Believe the one like the first one, was like a regular to line 16 character. LCD This is a particular graphics based one and we can whack a component in here and that's what the numbers are there for.

It's got three different terminals and it's got presumably duplicated over here. I Haven't tried it for a power transistor pads and you can plug a component into any part of that. Just power it on and it simply does it. Test there it is 100 ohm resistor between pins 1 and 3.

Beautiful! So yes I have no idea what firmware version this is running. Want very what you know schematic of variant this thing is. it's just a generic eBay M 3 to 8. So yeah, take that as it is now.
One of the first problems I have with this thing is, well, this particular unit in particular is the backlight. so let's switch it on and it's just like it's pissing away the power. Like why they need that backlight I've got a capacitor in there now a hundred n like a lot of that will be the backlight. Like why? Frustrating.

Anyway, this thing is really quite jazzy. Look if I put a transistor in there. just got one out of the junk tin but junk bin? what is it a B D One three seven I think it is. let's pair it on and have a look and I do like the automatic nature of this.

it is very nice look at that. It's automatically identified the transistor which you know, base collector emitter on which particular pin there and it gives us the Hf E and the forward voltage curve. but at what current? I don't know so we can actually take that, flip it around and see if it works the same. You basically gotta press the button each time it just reap hours It basically there we go.

look at that. Beautiful. So there's obviously a lot of refinement that's gone into this firmware and I'm sure a firmware is totally different across many different variants of this the countless different variants of this product. but this one I mean Joe I Tried resistors, capacitors and transistors now and it's just very nice.

So yeah, I'm huge thumbs up to this. Where this originally comes from, Who's writing this code? who's building it? I Don't know the history behind this is it's probably some huge mashup of code over time I Don't know if anyone's like that, does anyone know the original developer of this? but I've seen projects like this for going back, you know, decades in the magazines and things like that. So I don't think it's particularly new and I guess I Don't mind the use of Ayas if socket like this for testing. It's okay, you know, like it's fine, especially for like seven bucks.

I Remember like seven bucks delivered I Remember when the ZIF socket like this used to cost seven bucks and text tool it doesn't have 3m on it doesn't so it's probably just something. Yeah, one hung low variant. anyway. I'm gonna try and fool the crap out of this thing.

Um, because I don't know what range of stuff at tests the I'll plug in a 7805 I Don't expect it to work at all. It'll probably confuse it and say it's something else, but let's try it. No, no unknown or damaged part. There you go, it didn't.

It went well. that's outside the bounds of what I know about. I Only know about these particular parts and it doesn't test like any ovens, so that's pretty groovy. Don't mind that at all.

Come on. can't fool it. Count full it. Surely it's going through all its routines now.

It doesn't know what that is. Nice. Doesn't know what a red LED is. There you go.

You can see it pulsing. Ah, there you go. And well, it says it's a diode, which is exactly what it is. It's just a light emitting diode and two volts.
and it says it even gives you the capacitance for the diode for path. isn't that? Jersey So I'll just repeat that. I turned it around and put it in different ones, yet that's pretty repeatable. Nice green diode there.

Sweet. We'll try a VN 10k MOSFET here, but why fail? It thinks it's an NPN transistor. Hmm, so that's interesting. It knows it's acting like a transistor, which it is.

It's just a MOSFET and it is an N channel MOSFET so it's got that right. And the HN It knows that the gain is massive, but it hasn't identified that it's actually a MOSFET instead of a bipolar. And as for capacitors, it just gives us capacitance. but I had it before it was showing up what's called V loss which a it was 0.1% which I like I can't get it to do it again, but I swear it came up there.

It is no point One percent. So I assume that's the dissipation factor. so let's compare that with a real LCR tester and see what we get. Ninety Four Point eight at one kilohertz I Believe the test frequency is yeah, it's not quite there, but for ballpark measurements like a component identification I mean it's just fine.

So I'm not going to quibble over that. And as for that voltage lost there, there you go. dissipation Factor: You know the point said. Point One percent 0.03 You're enough.

Ah-ha It starts to give us more info. if we had put an electrolytic in there I Was wondering if it was going to do the ESR and certainly it does. 1 point 6 Ohms Forty Eight Point Eight Eight with a 1% dissipation factor and we're getting one point. Six owns there, which is pretty good for the ESR Once again, for component ID it's it's doing the job just fine.

Okay, so let's try the resistance over a entire range here. I Wouldn't quibble over anything less than 1. Ohm I haven't included test leads here, so that's just fine. Ten Point: Eight hundred and one thousand and nine Ten Point Oh 801 Getting a little bit out, but you know what? Meg's still pretty schmick.

see if we can do ten Meg Hey, that's not bad at all I am liking that. Let's say let's go out to say something difficult like 50 Meg That's not easy to yet. no unknown part. So what does it do go up to? you know, 20 mega so that's fine.

That's great so that seems to be reasonably accurate over the entire range. Don't mind that at all. Okay let's try a Big Cap 2200 Microfarad Electrolytic. Let's go it's I measured at 1869 on my LCR meter and I was at 0.05 ESR 0.18 It's a little bit out and 1965 but like it doesn't matter I'm happy with that just for component identification.

That's a winner, but you saw it there had point nine percent V loss and like that doesn't match anything doing with any sort of at one kilohertz the dissipation quality factor of this thing. So I'm not sure what's going on there now. it's supposed to be able to measure our MOSFETs but of course you saw a tyre fail with that V in 10k one there. So let's put in this IRF 6/10 and give that a bowl.
I'll be very impressed. if it can, it's supposed to do the A Wow Okay, consider me suitably impressed. Look at that. that's impressive N channel mosfet even get like in it shows the internal a diode and let's whack that around like that.

Okay, so I didn't like the V in 10k one, but it certainly does the business on this. I RF 610 is very impressive and really you don't care about the parameters that much. Is not a you know a precision bit of kit, it's a component identifier essentially, so you know that's pretty much all you want. Let's try one again.

We've got an IR F9 double one o P channel MOSFET so let's give that one a bill. Nice. haha. that's that's worth its weight in gold.

And let's do a D soldered salvaged 50 no6 shall we? Pretty standard part on I can't handle the Salter on the pins all that well. Let's give that a bell hang on. might not be making contact. Ah works a treat.

Winner winner chicken dinner. Okay let's try a surface mount bipolar. He got a double to double to for those. Play at home.

let's if we can, that's me. I'll see I made a turning off so I'll hold it down on there I Don't like those pads but it's obviously working in this case. Neat. All right, let's try 3.9 volt Zener Diode.

See what we get Hey look at that that is. Bang on to what you want. like it doesn't tell you it's a Zener diode, but it's implying it's a Zener diode because it's got the forward voltage yet it's not quite there. 3.9 volt.

Second only going at these low voltages for these levels, then it's going to depend heavily on the test current. So yeah, don't like. that's good enough, right? And then it knows that the diode in the opposite direction is your standard silicon drop like that. So from that you can infer it's a you know, three point five ish volt.

Zener No. Just got another little ceramic cap here, but you can see that I'll show you that the they dissing what the supposed dissipation factor is going to be. You know it. It's fairly out on this, so I wouldn't really take that as anything meaningful.

You know 0.6% V loss. You know it's near enough on the capacitance. just use it for component ID It seems to be grossly out on depends. Maybe there's a sweet spot of capacitance where you know it does fairly well on that, but you know some I've measured just aren't anywhere even in the ballpark.

and I just did a little little are thousand micro Henry or one milli Henry inductor surface-mount inductor there just by holding it on there and that did a reasonable job. There you go. there's the resistance of that and the adduct answer that at one Kilohertz, so it's pretty close nice and that's a 10 micro Henry inductor but it doesn't seem to really look at the resolution there. It's pretty terrible and it can't measure a 1 micro Henry at all.
It just thinks it's a resistor and well, that's fine. It's got a lower limit so there you go. I'm actually are very impressed by this little thing. It's amazing what you can get out of just a little 80 mega micro.

Some very clever Us software that's no doubt I've been much refined over time and a couple of passives and other stuff. There's a couple of trainees in there, a few diodes, you know there's really nothing to these things and it you can build these yourself. I'm like there are countless designs out there apparently. and I'll link in the Eevblog forum to this thing.

How? 156 pages of it so for seven bucks? deliver. This thing is just magical. Um, definitely get one. but I'd Recommend.

Like maybe get like spending a bit more and getting one that has a case with proper banana Jack's on or something that you can plug. you know, little LCR type test leads into or something like that. Or you can make your own. You can just buy the bare-bones one like this and you know you get rid of the ZIF socket or even have it on the front panel.

Make your own case. Do what a 3d printed case? Do whatever. Make a little do-it-yourself project out of it cuz these things are quite impressive. Don't use it as a substitute for a real LCR meter to take, you know, quantitative measurements of parts.

Um, that's not what's it's for. it's for, you know, a basically the component. Identify a go/no-go tester. You know it gives you a ballpark figure.

It seems reasonably accurate though for various capacitances and resistances, and it doesn't go that low in inductance and stuff like that. But for transistor identification like I wouldn't be taking the beedo for granted. and you know stuff like that. So this is a large community of people Actually, you know, hacking around with these things and changing the firmware and changing the design.

and you know, doing their own builds and things like that, which is fantastic. So it's definitely worth having one of these things in your kid. Especially, You know, for the price, if you're on a budget, then you know seven bucks delivered for a component identifier and basic measure. You know, basic measurement tool like this.

just fantastic and almost go practically can't be beat. And but there are tons of variations of this. as I said, so apparently can. Well, some others I've read do I? you know, Scr, thyristors and stuff like that I don't have any of those handy here, but it's impressive the amount of components that they can do and it can do it like MOSFETs like that? That's just fantastic.

Anyway, hope you enjoyed that. If you did, please give the video a big thumbs up. And as always, discuss down below, catch you next time you.

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By YTB

20 thoughts on “Eevblog #1020 – is a $7 lcr / component tester any good?”
  1. Avataaar/Circle Created with python_avatars DoIT4Kix says:

    @ EEVblog (Dave) are we at 20 years running since the first atmel code? I remember working on that project back in the day … the original was just an atmel and the data sent over rs-232 with some shitty visual basic or delphi code I wrote back then … ( It's been so long I really can't remember ) not portable NO LCD , NO 9v battery, no smd pads for the little tranny etc .. etc .. it was more of a bench-top concept at the time … but, of course it had the zif socket ! I'm glad to see it has evolved to a really handy portable jobbie ! I have the updated binaries if you want to flash the atmel chippies … to un-chinese it ! all you need to do is solder a few wires and run my patch and it will be much more accurate ! ๐Ÿค”

  2. Avataaar/Circle Created with python_avatars Mitch Scherer says:

    This is a fantastic microcontroller project from Karl-Heinz Kรผbbeler (TransistorTester with AVR microcontroller and a little more Version 1.11k).

  3. Avataaar/Circle Created with python_avatars Aleksandar Andjelkovic says:

    Can the tester read JFETs? On my tester it shows two resistors. It's at the JFET that I think is broken. The other day I received new JFETs J111 from China for my Fender Frontman amplifier, but unfortunately they also show the same two resistors! Can someone help with the interpretation? Is there a possibility that the JFETs were not declared and that defective elements arrived from China? Thank in advance!

    P.S. Also, in the application notes for the Mega328, I saw that the JFETs are tester readable.

  4. Avataaar/Circle Created with python_avatars Nofer Trunions says:

    I don't know enough to use a "full grown" LCR meter – I'm looking for something very rudimentary to test caps in circuit if possible (ESR in circuit most reliable?) People complain/have problems with $100 testers so this one sounds bang-for-buck winner!

  5. Avataaar/Circle Created with python_avatars Joe Rogan PodFantasy says:

    Working batteries don't get recognized from this device but a dead one shows up as a diode.

  6. Avataaar/Circle Created with python_avatars TOM says:

    At which frequency the esr is measured? Thank you.

  7. Avataaar/Circle Created with python_avatars CHARVESTER says:

    Won Hung Lo. Haven't heard that in awhile. Made me chuckle.

  8. Avataaar/Circle Created with python_avatars kalli71 says:

    i read somwhere to place Zener Diodes in the lower 3 pins. marked with ZAA on some devices

  9. Avataaar/Circle Created with python_avatars Rishad Alayan says:

    this is developed by a startup 'boatz embedded' from Kerala,India .the man behind this is the founder of the same company Mr. Anoop Mathew

  10. Avataaar/Circle Created with python_avatars Vk says:

    Can we test ic

  11. Avataaar/Circle Created with python_avatars Jim Taylor says:

    Hi Dave, Love the video. I've got a literally a pile of old 2N3055 power trannies. Will this little gadget test them with suitable wires soldered to their pins to enable plugging them into the tester ZIF socket? what are the two empty pads for just above the dustbin? Thanks.

  12. Avataaar/Circle Created with python_avatars Uli Herrmann says:

    Found this about history (instructables):

    Ideas behind this kit is started in 2009 by Markus Frejek as a thread on a forum.

    Later (in 2012) Karl-Heinz Kรผbbeler started to work on the project.

    this project continued to be more known, it was implemented in various forms over the time. Some enthusiasts have made it on breadboard, some have designed their own PCB's, single or dual layer; with thru-hole or SMD components… and so on.

    Also, over the time, have appeared variants with graphic display.

    The original diagram released by Markus in 2009 is what they still use 2023… There just some optimizations about 9V battery power supply and other displays. Original display was a HD44780 16×2 LCD.

  13. Avataaar/Circle Created with python_avatars Jim McLay says:

    Could this damage an electrolytic capacitor by reverse charging it ?

  14. Avataaar/Circle Created with python_avatars 69Dartman says:

    Thanks to seeing this video just today I ordered one of the latest versions with a color oled display in a case with test leads and some misc parts to test it with. 21.84 shipped from New Jersey to my place in Portland Oregon. I remember trying to find a capacitor tester back in the day and I have a couple transistor testers but not a all in one unit with a nice display. Of course back then there weren't any, at least none I could afford.
    I might not use it a lot now but I still fix my own stuff when it breaks and this will be so handy.
    It can even show remote IR wave forms and has a rechargeable battery built in.

  15. Avataaar/Circle Created with python_avatars loopvogel01 says:

    What do you expect for 10 bucks? For the money it is a multifunctional tester wich you can not compare with a 400 dollar meter.

  16. Avataaar/Circle Created with python_avatars albert magician says:

    Mark the TFXTTDDL inserting tool. This is no good. A genuine TEXTTOOL cost more than $7. This is a knock off and is deceptive. The original author is German and there is no improvement for the original design.

  17. Avataaar/Circle Created with python_avatars zos says:

    March 2023. Now $20 posted. Talk about inflation!

  18. Avataaar/Circle Created with python_avatars Davidut55 says:

    I zapped two of these with charged capacitors. First one, had a bunch of psu apfc main caps at 220uf 400v that had broken legs inside/ corroded. Initially they tested like 2000nF, after cutting the open was curious to see the actual value, but one had still a charge in it and shorted the mega328 chip.
    The second one, replacement for the first, a tc1 was toying with it after it arrived, measuring a capacitor but put in the pins market with K A A, the capacitor charged up from these pins and when moved to 1 and 2 pins mega328 burnt same as first. Now trying to get some mega328 and the firmware and some adapter to try and fix both.
    Really wish they had some kind of voltage protection!

  19. Avataaar/Circle Created with python_avatars Christopher Tadeo says:

    ๐Ÿ˜€

  20. Avataaar/Circle Created with python_avatars WackyT08 says:

    Have been using one of those for about the past 4 years, and it's been solid. Love it.

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