$20 LCR ESR Transistor checker project

[Yuriy_K]

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.

[Cosmic_Starlight]

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

[Yuriy_K]

You need to look for similar capacitors, specifically film ones.

[madires]

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!

[Yuriy_K]

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...

[bobrov1989]

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.

[snapper]

hello Yuriy
have you documented the changes to the circuit somehow so that I can insert them into my layout if necessary?

[Yuriy_K]

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.

[madires]

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 -?

[magic]

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?

[Feliciano]

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.

[Cosmic_Starlight]

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

[Yuriy_K]

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.

[indman]

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.

[bobrov1989]

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 - 🙃

[indman]

bobrov1989,read carefully what I wrote above. There is no need to supplement this project with features that may confuse the user.

[madires]

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.

[bobrov1989]

бобров1989 ,read carefully what I wrote above. There is no need to supplement this project with features that may confuse the user.

I have a different username (not sure what you wanted to show by changing it in your quote) and I've read your reply (replied to a different user if you read my post). Wanted to see if there any other ideas, thanks for your patience.

[Yuriy_K]

I Loss doesn't show for tantalum I had problems with - it has painted dot without any other signs.

Enable SW_CAP_LEAKAGE in config.h and see the result

[Yuriy_K]

hello Yuriy
have you documented the changes to the circuit somehow so that I can insert them into my layout if necessary?

Here is a simplified diagram with the latest changes.

Yes, the converter has been modified and tested yesterday.
There are no errors in the circuit.
All capacitors are ceramic, for operation at high frequencies. The output capacitor of the converter C17 must have a working voltage of at least 50 V.


NJ300A was used to adjust the frequency of the Arduino Mega 2560 quartz generator. The capacity of the cable wires is used. A deliberately larger section of known capacity is shortened to the desired frequency value. Control is carried out by the value of the output frequency period of 1 Hz with an accuracy of up to 6 digits.

[Cosmic_Starlight]

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.

i mean yeah it does work its just slightly bothersome that whenever i need to measure big caps the tester cant detect it on its own and i have to manually go into the capacitance test

oh and btw i did buy today some film caps but no store had anything that wasnt a polyester one, so i bought 3 a 330nf, some other i cant remember and a 1000nf one, and i ended up using the 1000nf one to calibrate it

the values of capacitance themselves dont seem to have changed much, however the issue that the capacitance test on 1--3 it kept climbing up seems to have been fixed, for example a 100k pf cap starts of at around  86k and then stabilizes at a little over 100k pf

same deal with the 2200uf cap tested manually through the menu, it only flickers between two values (and the vloss and esr accordingly)

its still on the stock 1% resistors, that i know that i need to upgrade to 0.1% in the future

but for now i think i can be happy with the device, now i think i need to start actually use it, learn it together with the big manual and actually use it to diagnose and fix stuff

oh and swap the kinda iffy MCU on the DIY kit whenever the programmer for it arrives

also i was reading the part of the manual on how the capacitance test works, and while i didnt understand most of it it seems that even between different units of the same MCU there can be different results and thats the purpose of calibrating the unit to bring them all together ? (but i guess theres only so much it can do)

[snapper]

Here is a simplified diagram with the latest changes.

hello Yuriy
has the voltage converter already been revised in the circuit you posted?
pin 16 of the HCF4060 should definitely be connected to VCC and not to Vin!?
best regards

[Yuriy_K]

has the voltage converter already been revised in the circuit you posted?
pin 16 of the HCF4060 should definitely be connected to VCC and not to Vin!?

Yes, the converter has been modified and tested yesterday.
No, specifically to Vin.

[Cosmic_Starlight]

Hello am looking for advice if i should re-calibrate my pre-built unit or not, its running 1.13K

(i dont know if it was calibrated with a film cap or not and if it was, was it a higher quality than the ones i got ? much less if even any capacitor was used as ive seen some videos on YT of calibration of their devices and not putting a cap in while the device is almost screaming for one to be put in)

i am only wondering because a 2200uf cap reads it as 2500ish while the DIY kit reads it as 2400ish
Although reading the K firmware manual here it seems that between different units of the same MCU there can be differences ? but idk if a 100ish uf difference is a lot or not

the showdata screen says for the pre-built
R0= .23 .24 .21      C0 37 38 39pf
Ri_Hi= 21.8                  39 39 39pf
Ri_Lo= 20.5           Ref_C= 9
                              Ref_R= -10

while DIY kit says
R0= .10 .11 .09      C0 41 41 42pf
Ri_Hi= 15.6                  42 42 42pf
Ri_Lo= 12.8           Ref_C= -15
                              Ref_R= 1

the capacitor i used for calibration of DIY kit is a 1uf +/-10% Polyester film cap, brand is Suntan

ive attached a photo of the capacitors in question

[Yuriy_K]

No one has cancelled the change in instrument readings depending on the warming up. Perform a self-test several times in a row, recording the readings, and set for your device when the readings stabilize. For increased accuracy, it is advisable to have a case. In the k-firmware menu, there is an item for adjusting readings for electrolytic capacitors. Polymer capacitors have the smallest deviations from the nominal value, as shown in the example.