$20 LCR ESR Transistor checker project

[hutale]

There is an LCR 2.9 bridge, meter kit with video found at http://youtu.be/ZQ33AR1ffFI and doc at http://lcr.is-best.net/en/ . This is a LCR/RLC/in-circuit C/ESR meter measuring L/C/R/Z/Rs/ESR/X/Q/D/Phase angle with 100Hz/1kHz/10kHz sine test signals, base on auto-balancing bridge technique. Maybe you are interested in it too.

[Richard Crowley]

All three of those gadgets on Dr. Le Hung's website look interesting to me.
But he doesn't appear to be actively selling them.  Or at least there is no indication on his web pages.

[Alex1]

All three of those gadgets on Dr. Le Hung's website look interesting to me.
But he doesn't appear to be actively selling them.  Or at least there is no indication on his web pages.

He does have a "get one" page but it looks like you need to email him about purchasing one.

http://lcr.is-best.net/en/build.htm

[diogoc]

It is possible to use the open source code in this chinese copy with graphic display?
http://www.aliexpress.com/item/Small-LCD-Transistor-Tester-Capacitance-ESR-Meter-Diode-Triode-MOS-LCR-NPN/1882283481.html

[Shock]

It is possible to use the open source code in this chinese copy with graphic display?
http://www.aliexpress.com/item/Small-LCD-Transistor-Tester-Capacitance-ESR-Meter-Diode-Triode-MOS-LCR-NPN/1882283481.html

Not without a lot of work and possible board modifications.

[hapless]

...possible board modifications.

What do you have in mind?

[diogoc]

The schematic should be similar, so only need a firmware with fonts and graphics compatible with that lcd

[madires]

It is possible to use the open source code in this chinese copy with graphic display?
http://www.aliexpress.com/item/Small-LCD-Transistor-Tester-Capacitance-ESR-Meter-Diode-Triode-MOS-LCR-NPN/1882283481.html

The k-firmware supports ST7565 compatible displays, but I don't know which controller the display of that clone got.

[hapless]

That LCD looks small... could it be a Nokia? There was an early attempt to use such a display.

[andrija]

I bought the graphical LCD version from EBay (fish...) that I stumbled upon while doing some other shopping and before I knew what it was and where it originated from. Now that I've read good part of this thread, I don't think I want to mess around with mine. I wouldn't mind buying another one, though, with the intention of being able to update its firmware. Looking at the documentation of the original project, there is a version for ATMega644 or 1284; there are schematics in that pdf and everything. Has crystal measurements (I think), DC-DC for Zener (again, I think), input protection with rail-to-rail zeners and tons of more parts than the one I've got, which doesn't have much more than a few R, a few C and uC and screen. But no one seems to be talking about it (ATMega644)? Does this actually exist (there seems to be code for it)? Can I buy it? Or do I need to design a PCB for it myself (if the software already exist, that's a viable option for me).

[diogoc]

That LCD looks small... could it be a Nokia? There was an early attempt to use such a display.

Is not a nokia lcd because this have a resolution of 128x64.

[madires]

Looking at the documentation of the original project, there is a version for ATMega644 or 1284; there are schematics in that pdf and everything. Has crystal measurements (I think), DC-DC for Zener (again, I think), input protection with rail-to-rail zeners and tons of more parts than the one I've got, which doesn't have much more than a few R, a few C and uC and screen. But no one seems to be talking about it (ATMega644)? Does this actually exist (there seems to be code for it)? Can I buy it? Or do I need to design a PCB for it myself (if the software already exist, that's a viable option for me).

I haven't seen any clone with an ATmega644 yet, so you're welcome to make a PCB yourself

[a1976888]

Hi,
I was looking for a cheap ESR meter to make in circuit capacitor tests.
Could someone who bought any of these tell me if this function is usable in real word repairing tasks, please ?
Which model did you buy ?
Thanks!

PS : Wonderful project ! 

[Shock]

I was looking for a cheap ESR meter to make in circuit capacitor tests.
Could someone who bought any of these tell me if this function is usable in real word repairing tasks, please ? Which model did you buy ? Thanks!

The ESR measurement can be used to tell you if the capacitor is failing even if the capacitance measures within spec. As for in-circuit testing your mileage may vary, it's highly dependent on the circuit your testing. This will not discharge your capacitor prior to testing. Nor do they offer input protection (at least last time I looked).

These $20 meters measure resistance and semiconductors as well as capacitance and ESR. They aren't really a replacement for the handheld meters (DER EE DE-5000 - great value) or more expensive proper bench top LCR meters which may offer larger measurement ranges and more accuracy. More expensive meters may be able to take 4 wire measurements for better accuracy.

In addition to capacitance value and ESR (equivalent series resistance) there is also Q (quality factor) which is its efficiency at frequency or inverse of D (dissipation factor). There is also IR (insulation resistance) which is the capacitors ability to withstand current leakage.  Using deduction combined with a multimeter and capacitance/ESR meter should get you through 95% of situations.

There is no best Chinese ESR meter as there is negative aspects in all of them. such as no programming header, no crystal, no external power, less accurate, bad connector design, shortcuts. So take your pick it's only $20.

[Shock]

PS : Wonderful project ! 

FYI the project is actually on this German website:
http://www.mikrocontroller.net/articles/AVR_Transistortester

When you buy a Chinese $20 clone in most cases your really buying the project where it was at a few years ago. You can modify and upgrade them if you have the skill, but the reason why they are so popular is they are dirt cheap.

[i4004]

All three of those gadgets on Dr. Le Hung's website look interesting to me.
But he doesn't appear to be actively selling them.  Or at least there is no indication on his web pages.

He does have a "get one" page but it looks like you need to email him about purchasing one.

http://lcr.is-best.net/en/build.htm

yeap, about 55eur in europe for meters (55eur each)..dunno about reflow controller....that would be about 70$ but dunno how much more for shipping to usa or elsewhere...ask him...he's a good guy.

the soldering on the meter pics i got looks very nice...

[a1976888]

I was looking for a cheap ESR meter to make in circuit capacitor tests.
Could someone who bought any of these tell me if this function is usable in real word repairing tasks, please ? Which model did you buy ? Thanks!

The ESR measurement can be used to tell you if the capacitor is failing even if the capacitance measures within spec. As for in-circuit testing your mileage may vary, it's highly dependent on the circuit your testing. This will not discharge your capacitor prior to testing. Nor do they offer input protection (at least last time I looked).

These $20 meters measure resistance and semiconductors as well as capacitance and ESR. They aren't really a replacement for the handheld meters (DER EE DE-5000 - great value) or more expensive proper bench top LCR meters which may offer larger measurement ranges and more accuracy. More expensive meters may be able to take 4 wire measurements for better accuracy.

In addition to capacitance value and ESR (equivalent series resistance) there is also Q (quality factor) which is its efficiency at frequency or inverse of D (dissipation factor). There is also IR (insulation resistance) which is the capacitors ability to withstand current leakage.  Using deduction combined with a multimeter and capacitance/ESR meter should get you through 95% of situations.

There is no best Chinese ESR meter as there is negative aspects in all of them. such as no programming header, no crystal, no external power, less accurate, bad connector design, shortcuts. So take your pick it's only $20.

Thanks for your clear answer.
I think that limitations you pointed out are ok for 20$.
I already have a DMM with capacitance measurement capabilites but I thinks that deduction plus capacitance measure are not enough to surely identify bad caps. It's the reason why I think I need at least en ESR meter to do that. And in circuit testing would be a really nice feature...

As per Chinese ESR meter I'd like to buy a model that could be upgraded with project improvements. No external power, accuracy and shortcuts would be no problem as I could fix them by myself. But crystal and programming header would be nice (or at least a socket 328)...

This one look nice (crystal, socket, large display, upgradable?) :
http://www.aliexpress.com/item/12864-LCD-GM328-transistor-tester-ESR-meter-Cymometer-square-wave-generator-Free-shipping/2052241237.html

[a1976888]

PS : Wonderful project ! 

FYI the project is actually on this German website:
http://www.mikrocontroller.net/articles/AVR_Transistortester

When you buy a Chinese $20 clone in most cases your really buying the project where it was at a few years ago. You can modify and upgrade them if you have the skill, but the reason why they are so popular is they are dirt cheap.

Are you talking about lacks of hardware or software ?

Thanks for the project link !

[andrija]

I am looking at the extended version schematics with ATmega644 and there are a few things I don't get. First, why do they say the DC-DC converter should be on a separate board? I am not even sure how would that work as they don't specify what exactly should be on that other board, I guess the whole section with the "button" and battery being the only inputs and TP5 (external test) being output; but why? Second, what do they mean by "button" annotation? Just a name for that connection point or is there supposed to be something else there?

[madires]

I am looking at the extended version schematics with ATmega644 and there are a few things I don't get. First, why do they say the DC-DC converter should be on a separate board? I am not even sure how would that work as they don't specify what exactly should be on that other board, I guess the whole section with the "button" and battery being the only inputs and TP5 (external test) being output; but why?

The idea is to keep the switching noise away from the test pins. It doesn't need to be another PCB, just have it separated from the main circuit. I've got two boards with DC-DC converters on the same PCB and got no issues so far (one board with a DC-DC converter module and the second one with a classic boost converter). Also I really recommend to have a dedicated LDO for the DC-DC converter. Otherwise it would cause some trouble to the 5V of the main circuit (voltage drop when button is pressed and triggering the MCU's brown-out-detection).

Second, what do they mean by "button" annotation? Just a name for that connection point or is there supposed to be something else there?

Seems to be just an annotation.

[andrija]

Thanks, I concur with what you are saying. Regarding separate regulator for the DC-DC, the extended schematics does have its own MCP1702-5 so it should be ok.

[hapless]

I have noticed something interesting about the tester. I have mine set to show me several measurements in a row. When I just turn it on normally, the measurement results stay on for a short while, and then another measurement is performed. If I go to the menu and choose Transistor to go back to normal operation, the result stays on the screen longer! Or at least it feels like it stays longer. How much longer, I don't know, seems somewhat random. I actually like this bug. I think there should be an easy way to be able to tell the tester to have the result on the screen for a longer or shorter time (a menu option, along with turning on and off nano for caps?).

Has anyone else noticed this?

[madires]

I have noticed something interesting about the tester. I have mine set to show me several measurements in a row. When I just turn in on normally, the measurement results stay on for a short while, and then another measurement is performed. If I go to the menu and choose Transistor to go back to normal operation, the result stays on the screen longer! Or at least it feels like it stays longer. How much longer, I don't know, seems somewhat random. I actually like this bug. I think there should be an easy way to be able to tell the tester to have the result on the screen for a longer or shorter time (a menu option, along with turning on and off nano for caps?).

Please try to press the test button a little bit longer when powering on the tester.

[hapless]

What for?

[madires]

What for?

For a longer display period.