Analog ESR meter design

[mariushm]

Re: Analog ESR meter design

^ i think this is the meter :

http://pro-radio.ru/measure/10248/

The links in the text point to an older and similar through hole version with source code and everything available.

[vhr]

Re: Analog ESR meter design

ESR/L/C/F/P/t meter
http://www.youtube.com/watch?v=a-mXYYr3KjY

[vhr]

Re: Analog ESR meter design

marcdima

[marcdima]

Re: Analog ESR meter design

marcdima
TV1,TV2-42TM026-RC
https://cdn.badcaps-static.com/pdfs/...bddb34ce25.pdf

all things are clear now thank you very much

[vhr]

Re: Analog ESR meter design

marcdima
TV1,TV2-42TM026-RC
https://cdn.badcaps-static.com/pdfs/...bddb34ce25.pdf

[marcdima]

Re: Analog ESR meter design

thank you Simurg
for the new link I see that you are the author of this great work
I like the way you made the testing pads for testing the surface mounted cap. , I try to do something similair .

thank you tom66 for the explanations
you're right it's very clever

for resistors I only found standard SMD 1R0
I think tolerance will influence on the accuracy of measurement , I do not have a choice .

[tom66]

Re: Analog ESR meter design

Unfortunately, this link does not work now
http://radiokot.ru/konkurs/10/
but luckily I saved the diagram (see picture)



I would really like a small explanation of this diagram
I'm not a pro of electronics but I have basic notion
I always learning in this field

I understood
In this diagram the power source is a 1.2V battery rechargeable

the transistor VT1 used as a constant current source to approximately 50mA current given

capacitor C2 and the transformer TV1 I think it is the oscillator

The 1 ohm Bridge Resistor for the measuring
I have a question here! to increase the precision we reduce the value of resistors to 0.5 ohm or less ,so it is possible to use the smd resistance of 0 ohm ? (ideal conductor is not going to be 0 Ohms when I measure these resistances 0 ohm with true rms multimeter I see 0.7 ohm )

another question the transformer TV2 I think used here to amplify the signal
What kind used here
what is he number of turns of the primary and secondary ...?

I appreciate your support my friends
thank you very much

I think I understand how this works (it's very clever)

The transistor is configured, with the transformer as a blocking oscillator, one of the simplest oscillators you can make, using just one transsitor. It also has a constant peak current characteristic because of this.

The 1 ohm resistors are to add a voltage which the diode VD3 drops to allow low-ESR measurement. The zero function removes the rest of the offset. The resistors must be 1 ohm to allow you to measure low ESR.

[Simurg]

Re: Analog ESR meter design

link: http://radiokot.ru/circuit/analog/measure/22/
forum: http://radiokot.ru/forum/viewtopic.p...60919#p1460919
transformer TV1 and transformer TV2 http://lightportal.at.ua/2011/SDUanalog/Shem07.jpg

[marcdima]

Re: Analog ESR meter design

To increase the resolution reduce the resistors to 0,5-0,3Ohms.
You can also increase the number of turns of the secondary winding of the transformer TV2.

Unfortunately, this link does not work now
http://radiokot.ru/konkurs/10/
but luckily I saved the diagram (see picture)



I would really like a small explanation of this diagram
I'm not a pro of electronics but I have basic notion
I always learning in this field

I understood
In this diagram the power source is a 1.2V battery rechargeable

the transistor VT1 used as a constant current source to approximately 50mA current given

capacitor C2 and the transformer TV1 I think it is the oscillator

The 1 ohm Bridge Resistor for the measuring
I have a question here! to increase the precision we reduce the value of resistors to 0.5 ohm or less ,so it is possible to use the smd resistance of 0 ohm ? (ideal conductor is not going to be 0 Ohms when I measure these resistances 0 ohm with true rms multimeter I see 0.7 ohm )

another question the transformer TV2 I think used here to amplify the signal
What kind used here
what is he number of turns of the primary and secondary ...?

I appreciate your support my friends
thank you very much

[mainfurer]

Re: Analog ESR meter design

I get zero. That was what all the trouble was about... getting it to read zero with the test leads shorted was quite an undertaking, and i learned a lot about stray coupling between wires in the meantime. There are only two test leads (woulda been awkward to use four), but with two pairs of wires going to them.

For checking PCB shorts you would need to change the frequency to 50Hz and increase the coupling capacitor values so the 50Hz signal passes unaltered. Much less trouble that way. PCB traces are inductive too so if using a high frequency you could have the surprise that a short does not read as such unless the probes are really close to it. Another application for an AC milliohm meter working at 50Hz is as a "ground loop buster" in troubleshooting PCB layouts.

HELLO!!! greets from Mexico, may i ask you for your final version of the esr add on for the dmm??? can you post please your pcb? so me and other can have a view of your impressive job thanks and hope to read from you soon

[Ryu.Hayabusa]

Re: Analog ESR meter design

Attached the schematic in ExpressPCB format and as a picture for those who don't want to install the software. ExpressPCB is quite a crude package but i've gotten used to it and i can't be bothered to learn anything else right now. The PCB needs some updates, it'll probably get posted when i find a suitable case for the meter, i'll have to shop around next week.

Is this the final design? I've been looking for a ESR meter I can build and attach to a DMM so I don't have to muck around with micros or display controllers.

[tom66]

Re: Analog ESR meter design

I think I figured out why constant-current meters are nonexistent.

With the constant-voltage design, the higher the ESR, the lower the dissipation in the cap. Remember, smaller caps have higher ESR, and worse heat dissipation.

The constant-current design means higher ESR caps get HOTTER. And when they're also smaller...

Not really. Most constant-current designs have a maximum compliance voltage - the point at which the current is unacceptably inaccurate. For one prototype meter I considered building, it was 1.5 ohms. Open circuit voltage was about 1Vp-p.

[vhr]

Re: Analog ESR meter design

To increase the resolution reduce the resistors to 0,5-0,3Ohms.
You can also increase the number of turns of the secondary winding of the transformer TV2.

[budm]

Re: Analog ESR meter design

Current through the cap will in mA or less range not enough to cause any heat.
IE: 10 Ohms ESR with constant current of 10mA will cause 100mV (about 1 milli-watt of power) feeding the reading circuit, which mean you can even use smaller curret source.

[marcdima]

Re: Analog ESR meter design

thank you guys I am trying to collect components

[Shocker]

Re: Analog ESR meter design

I think I figured out why constant-current meters are nonexistent.

With the constant-voltage design, the higher the ESR, the lower the dissipation in the cap. Remember, smaller caps have higher ESR, and worse heat dissipation.

The constant-current design means higher ESR caps get HOTTER. And when they're also smaller...

[MDOC]

Re: Analog ESR meter design

thank you MDOC I did the translation I wanted to say rather it is not well translated

OK. I removed the image because it had sensitive information on it.

[vhr]

Re: Analog ESR meter design

marcdima
Of C2 and TV2 depends maximum stretching of the scale.I have a scale of 0-5 Ohms.Resolution can be increased to 0,001Ohms!Then the full scale will be 0-0,5Ohms.
For LOW-impedance(LOW ESR)capacitors that is enough.

[marcdima]

Re: Analog ESR meter design

thank you MDOC I did the translation I wanted to say rather it is not well translated

thank you vhr this is what I wanted to know
and thank you again for useful documents

I need just know the capacitor C2 = 6200* !!! , and I give a try . What is the value of this one ?

[vhr]

Re: Analog ESR meter design

marcdima
Works fine.Transformers HDT of old TVs and monitors.
Resolution-0,005Ohm.
VT1-BC547
VD3,VD4-1N5819
Calibrate these resistors and capacitors.
https://cdn.badcaps-static.com/pdfs/...3abfb7040a.pdf

http://www.capacitorlab.com/capacitor-types-polymer/