Author Topic: $20 LCR ESR Transistor checker project  (Read 4237288 times)

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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #9825 on: December 21, 2024, 04:20:37 pm »
From 1.54m's config.h:
Code: [Select]
/*
 *  display C_be (base-emitter capacitance) for BJTs
 *  - uncomment to enable
 */

//#define SW_C_BE
 

Offline bobrov1989

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Re: $20 LCR ESR Transistor checker project
« Reply #9826 on: December 21, 2024, 09:20:48 pm »
From 1.54m's config.h:
Code: [Select]
/*
 *  display C_be (base-emitter capacitance) for BJTs
 *  - uncomment to enable
 */

//#define SW_C_BE

Sorry, you're right - did something wrong when merged the file  |O
 

Offline Cosmic_Starlight

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Re: $20 LCR ESR Transistor checker project
« Reply #9827 on: December 22, 2024, 03:16:43 am »
Hello, so my new two units arrived a couple of days ago, two AY/AT one pre-built, one DIY kit (both are 16mhz versions surprisingly) running 1.13K

the pre-built has never asked me to calibrate it
and am just about done with the DIY kit, only need to solder the ZIF socket and the connectors for the freq,volt,pwm (it turns on and it says as expected that theres no component in but nothing about calibration)

anyway, i was wondering if the way or the wires or how i positioned them in the ZIF socket is the correct way to calibrate it or am i doing it wrong and will i damage the device  doing it that way? (as in the attached photo, its of the 1st bad unit)

also would a 10uF capacitor work for the 2nd part of the calibration process ?

those two wires are CAT5E that ive had on a protoboard since forever (like 10 years ago)
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #9828 on: December 22, 2024, 08:22:20 am »
The short wires should work fine. And for the capacitor use a film cap 220 nF up to 2.2 µF.
 
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Offline Feliciano

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Re: $20 LCR ESR Transistor checker project
« Reply #9829 on: December 22, 2024, 12:58:18 pm »
The most likely way of damaging a CTester is to apply more than 5V to its terminals. Doing a short among them for adjustement shouldn't arise any trouble (provided the unit was assembled without errors).

On the other hand, when you are soldering resistors, you cut some legs. You could grab three of those and twist-solder it to make a "fork" (E-shape) and keep it in your toolbox for when you want to adjust your unit again (or you can do the same with 3 AWG24 or thinner wires if you like).
 
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Offline Fuzzy Star

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Re: $20 LCR ESR Transistor checker project
« Reply #9830 on: December 22, 2024, 01:07:57 pm »
...
also would a 10uF capacitor work for the 2nd part of the calibration process ?

And have you read the project documentation? there are FAQs, and long manuals with many details that allow you to understand how this OSHW works, and hence, to troubleshoot it.
 

Offline Cosmic_Starlight

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Re: $20 LCR ESR Transistor checker project
« Reply #9831 on: December 22, 2024, 04:01:15 pm »
I had forgotten about the faq, didnt know it had manuals for specific firmwares, the manual for 1.13k specifies a range between 100nf---20uf  so i will use some of the brand new 10uf caps for the calibration

Thank you very much
 

Offline Jacon

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Re: $20 LCR ESR Transistor checker project
« Reply #9832 on: December 22, 2024, 04:41:13 pm »
Hi Marcus,

Somehow missed the previous (1.53) one - enclosed pls find updated polish_2 translation file

Sorry
Jacek
 
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Offline Yuriy_K

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Re: $20 LCR ESR Transistor checker project
« Reply #9833 on: December 22, 2024, 06:03:08 pm »
I had forgotten about the faq, didnt know it had manuals for specific firmwares, the manual for 1.13k specifies a range between 100nf---20uf  so i will use some of the brand new 10uf caps for the calibration
The author has set out all the requirements for capacitors, and Madires showed you the recommended range based on his experience. Below is the author's text...

For the second part of adjustment you must connect a capacitor to pin 1 and pin 3. This capacitor
should have a good quality factor and should have a capacity between 100nF and 20 uF. It should
be film capacitor, as far as possible not a ceramic capacitor und in no case a electrolytic capacitor.
You don't need to know the exact value of this capacitor.

 
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Offline Cosmic_Starlight

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Re: $20 LCR ESR Transistor checker project
« Reply #9834 on: December 23, 2024, 02:41:11 am »
I had forgotten about the faq, didnt know it had manuals for specific firmwares, the manual for 1.13k specifies a range between 100nf---20uf  so i will use some of the brand new 10uf caps for the calibration
The author has set out all the requirements for capacitors, and Madires showed you the recommended range based on his experience. Below is the author's text...

For the second part of adjustment you must connect a capacitor to pin 1 and pin 3. This capacitor
should have a good quality factor and should have a capacity between 100nF and 20 uF. It should
be film capacitor, as far as possible not a ceramic capacitor und in no case a electrolytic capacitor.
You don't need to know the exact value of this capacitor.


since i unfortunately i cant be sure of the quality of locally bought capacitors (even film ones) i will have to pull one out from an old hifi stereo amp just to calibrate it properly it seems
 
and from the list attached the only one that fits the description of >200pf <2uf is C125 which is 390pf and is silvered mica, problem is its from the early 70s so hopefully it hasnt degraded much
 

Offline Yuriy_K

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Re: $20 LCR ESR Transistor checker project
« Reply #9835 on: December 23, 2024, 03:01:55 am »
You need to look for similar capacitors, specifically film ones.
 
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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #9836 on: December 23, 2024, 08:58:48 am »
and from the list attached the only one that fits the description of >200pf <2uf is C125 which is 390pf and is silvered mica, problem is its from the early 70s so hopefully it hasnt degraded much

220 nF - 2.2 µF film cap!
 
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Offline Yuriy_K

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Re: $20 LCR ESR Transistor checker project
« Reply #9837 on: December 23, 2024, 03:04:38 pm »
Hi Reinhold, over the past two years I have added changes to the circuit for testing quartz and ceramic resonators up to 30 MHz. A converter for testing zener diodes up to 24 volts, I don't remember exactly what improvements were made to the k-firmware. Here is the current firmware and some measurement examples...
 

Offline bobrov1989

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Re: $20 LCR ESR Transistor checker project
« Reply #9838 on: December 23, 2024, 04:03:07 pm »
coding in C is not my specialization (I'm JS dev), so I want to ask if it's possible to add code to detect caps polarity. So far I checked cap.c source files and it looks like during ESR check cap is tested in both directions, is it possible to use similar mechanism to depect polarity?

The problem I have when testing cap that some tantalum caps and Soviet polarized ones have no or misleading marking for positive pin. A few times I was forced to resolder such caps 😅 - so would be cool if component tester would show which pin is +.

I already extended Capacitor_Type with IsPolarized and PosPin fields and added a code to show + char near pins on display. So far struggling with actual detection code.
 

Offline snapper

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Re: $20 LCR ESR Transistor checker project
« Reply #9839 on: December 23, 2024, 04:16:43 pm »
hello Yuriy
have you documented the changes to the circuit somehow so that I can insert them into my layout if necessary?

« Last Edit: December 24, 2024, 12:33:29 am by snapper »
 

Offline Yuriy_K

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Re: $20 LCR ESR Transistor checker project
« Reply #9840 on: December 23, 2024, 05:27:07 pm »
I have recently published separate solutions for measuring quartz crystals and input frequency, but I am thinking of redesigning the voltage converter for checking zener diodes and am not ready to publish it yet. The issue with the measurement current needs to be resolved.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #9841 on: December 23, 2024, 07:32:34 pm »
The problem I have when testing cap that some tantalum caps and Soviet polarized ones have no or misleading marking for positive pin. A few times I was forced to resolder such caps 😅 - so would be cool if component tester would show which pin is +.

Is there any reliable way to detect + and -?
 

Offline magic

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Re: $20 LCR ESR Transistor checker project
« Reply #9842 on: December 23, 2024, 10:13:51 pm »
Hi, can anyone quickly tell what may be wrong with this one?

3 pin semiconductors: mostly misidentified

three way short: 0.2Ω between 1 and 2
2-3 or 1-3 short: nothing
1-2 resistance: only up to a few Ω and not very accurate, later nothing
1-2 LED: OK
1>3 or 2>3 LED: blinks, but nothing
3>1 or 3>2 LED: doesn't blink, nothing

Sounds like pin 3 is blown? |O
 

Offline Feliciano

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Re: $20 LCR ESR Transistor checker project
« Reply #9843 on: December 23, 2024, 11:05:26 pm »
My first thought would it be TP3 is damaged. To confirm you could measure whether there's some voltage present there (compared to ground) when testing. You could also measure continuity from the socket to the MCU itself.
 

Offline Cosmic_Starlight

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Re: $20 LCR ESR Transistor checker project
« Reply #9844 on: December 24, 2024, 01:54:26 am »
Hello, i am aware i might seem like a bothersome fly by this point and i apologize

i only have one slight problem (not so much a problem but more of an minor inconvenience)

so i got this 2200uf 50v capacitor that i tried measuring that i have some issues with that i think ive tracked down to the MCU
(yes i made double sure it was discharged)

basically i put the cap between 1-3 on the DIY kit and it turns on but when it says testing and its around the 3rd or 4th suspension point it shuts off, the pre built kit doesnt exhibit this behavior

however, turning on the diy kit with no component on and then manually selecting capacitance test from the menu then putting the cap in it measures it correctly

so i swapped the MCU between the prebuilt and the DIY kit and the same behavior can then be seen on the pre-built kit with DIY MCU, and DIY kit with Pre-built MCU works normally

there was even one point that even a 100k pf  ceramic cap caused it to shutdown, not even the 10uf cap worked, but now its back to only the 2200uf cap having issues on DIY MCU

could this be caused by the improper calibration capacitor usage ? or is it just a slightly defective MCU ?

btw on pre-built it measures around 2500uf and on DIY it measures around 2400uf

i dont really mind much tbh, was just wondering if this is normal behavior due to improper calibration or just an MCU issue
 

Offline Yuriy_K

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Re: $20 LCR ESR Transistor checker project
« Reply #9845 on: December 24, 2024, 02:27:41 am »
The problem I have when testing cap that some tantalum caps and Soviet polarized ones have no or misleading marking for positive pin. A few times I was forced to resolder such caps 😅 - so would be cool if component tester would show which pin is +.

Is there any reliable way to detect + and -?

You need to look at the polarity of the capacitor connection and the information displayed on the screen. And of course, read the author's description.
 

Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #9846 on: December 24, 2024, 07:49:20 am »
Is there any reliable way to detect + and -?
There is no reliable way to reliably determine the polarity of such capacitors using this tester. There is not enough test voltage.
The leakage current may vary and differ significantly for different types of such capacitors with different operating voltage.
« Last Edit: December 24, 2024, 08:13:08 am by indman »
 

Offline bobrov1989

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Re: $20 LCR ESR Transistor checker project
« Reply #9847 on: December 24, 2024, 09:41:19 am »
You need to look at the polarity of the capacitor connection and the information displayed on the screen. And of course, read the author's description.

I Loss doesn't show for tantalum I had problems with - it has painted dot without any other signs. Another problematic one was 47uF Soviet cap without any marking and longer lead appeared to be - 🙃
 

Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #9848 on: December 24, 2024, 09:45:52 am »
bobrov1989,read carefully what I wrote above. There is no need to supplement this project with features that may confuse the user.
« Last Edit: December 24, 2024, 03:59:23 pm by indman »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #9849 on: December 24, 2024, 09:58:06 am »
could this be caused by the improper calibration capacitor usage ? or is it just a slightly defective MCU ?

The tester should work also without the self-adjustment. But measurement values could be a bit off.
 
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