5 Transistor ESR Meter Design

[m3vuv]

is there any reason c3 is 22nf not 10 nf as in the original schematic?

[thejazzcat]

Hi,

I'm building this ESR Meter but haven't been able to get the analog meter. I have a couple of questions.

Could I use the 60uA scale on my Kaise SK-120 Multitester as a substitute? Any risks on the unit that I should consider?

Can I replace the square wave oscillator for any of the available designs on the web? I have seen some IC555 that are quite simple and can have some controls to vary the frequency and the voltage output (would that be a handy thing to have with this tester?).

All the best.

[strawberry]

I'm building this ESR Meter but haven't been able to get the analog meter.
All the best.

100uA
https://www.aliexpress.com/item/32360422161.html

[Texmisure]

Hello Jay_Diddy_B,

Can you add a led indicator for a shorted capacitor? Thank you for your great job.

[Jay_Diddy_B]

Hi group,

To celebrate the 10th anniversary of the 5 transistor ESR Meter and my first post on the EEVBlog, I am working on a new version with an additional circuitry to detect a shorted capacitor.

Here is a little teaser:



I have added two transistors to detect the shorted capacitor.

I will share more information when I have built and tested design.

KICAD version 5 is being used for the design. I will release all the files when they are ready if somebody wants to convert the design to thru-hole.

Best regards,

Jay_Diddy_B

[kripton2035]

where is the led ?

[Jay_Diddy_B]

kripton2035 and the group,

where is the led ?

TP1-TP2  9V Battery
TP3-TP4 LED to indicate the capacitor is shorted
TP5-TP6 Capacitor being tested
TP7-TP8 Meter and zero potentiometer, in series


Best Regards,

Jay_Diddy_B

[thejazzcat]

Hi,

I just finished my meter. I have a final question, what diodes can I use for meter protection? I see them on some of the builds on this thread.

Thanks in advance.
CE

[Jay_Diddy_B]

thejazzcat and the group,

Hi,

I just finished my meter. I have a final question, what diodes can I use for meter protection? I see them on some of the builds on this thread.

Thanks in advance.
CE

There are two kinds of diodes:



In the red area use 1-3A silicon diodes, the type is not important, they protect the ESR meter from a charged capacitor. Do not use Schottky diodes.

In the blue area use small-signal 15mA Schottky diodes. I use 1N5711. These are the rectifier for the meter.

Best Regards,
Jay_Diddy_B

[Jay_Diddy_B]

Hi group,

A quick update on the new design, 7 transistors including shorted capacitor indication.

I have sent the files to JLCPCB for fabrication and assembly. I have opted for slow shipping. I will add the parts that they do not have in the basic collection. It will be a few weeks before I see the boards.




Best regards,

Jay_Diddy_B

[kkamel]

I used BAT 85 small signal diodes and they are working exactly the same as 1N5711.

[zoltanh]

Hi,

Thank you. When do you plan to release the files?

[Jay_Diddy_B]

Zoltanh and the group,

Hi,

Thank you. When do you plan to release the files?

I plan to release the files after I have tested it. I am confident that the original 5 transistor circuit will work properly. The additional two transistors to detect the shorted capacitor has been tested in LTspice. It works in simulation.

This is the first time I have had boards assembled by JLCPCB. They are saying 1-2 days to build the PCB and another 1-2 days to solder 80% of the components. I will add the 20% of the parts that they do not have in their basic catalog. Then there is shipping, by DHL from China to Canada. I expect that I will get them between Christmas and the New Year.

Send me a PM if you can't wait 

Jay_Diddy_B

[kkamel]

Hi Jay,
I have been using your tester for almost two years now and I am using 9V battery and 7805 regulator and I have noticed that if the battery drops below 7.5V the behavior of the circuit is not stable always requires calibration. Is it possible to reduce the threshold of the circuit by using 3.3V regulator instead of the 5V? Another question is it possible to use switching mode DC-DC converter to reduce the consumption or the noise of smps will impact the circuit accuracy?
Thanks

[iMo]

Do use a "5V low dropout regulator" or "LDO".. The 78L05/7805 needs at least 2.5-3V over the 5V at its input to provide a stable output (plus minus, it depends on the manufacturer). Also the vintage 78xx series takes 5-7mA just for the regulator itself thus killing your 9V battery soon.
The low dropout regulators are usually happy with less than 0.6V and their quiescent current is at least 10x lower...

[kkamel]

I will search for an LDO alternative.
Thanks

[strawberry]

I made this LDO with UV OV OC

[kkamel]

This is too much for battery regulation I was searching for direct replacement LDO and low quiescent current.

[strawberry]

standby ~2uA
operation ~1mA
TLV431 currents could get into uA range

[Jay_Diddy_B]

hi group,
the new version uses the AMS1117-5 regulator. It needs a minimum load, but the dropout voltage at the ESR meter current is less than 1V and the price is very low.


Jay_Diddy_B

[bostonman]

I have been using your tester for almost two years now and I am using 9V battery and 7805 regulator and I have noticed that if the battery drops below 7.5V the behavior of the circuit is not stable always requires calibration.

Is using a wall wart a better alternative or is it too noisy?

[Jay_Diddy_B]

Is using a wall wart a better alternative or is it too noisy?

A wall wart will work fine. You could use a regulated wall wart and short out the regulator.

If you use a wall wart, check out DiodeGoneWild on YouTube. A lot of wall warts are dangerous with only enamel insulation between the output and the mains.

Link:
 
I use my ESR meter for a few minutes each year. With this low level of use a 9V battery works fine.

Jay_Diddy_B

[Texmisure]

Hi group,

To celebrate the 10th anniversary of the 5 transistor ESR Meter and my first post on the EEVBlog, I am working on a new version with an additional circuitry to detect a shorted capacitor.

Jay_Diddy_B

Thank you, we are ok for the next 10 years😉

[alexandre MC]

Olá..
Poderia me dizer qual a tensão entre TP3 e TP4.  Montei o esquema e as tensões ficaram iguais as da foto, porem meu amperímetro ( 50 microampères ) não oscila.

[kripton2035]

another possible improvement : add the same high voltage protection than on the esr to voltmeter adapter...