Re: Looking for a better in circuit ESR meter

Miguel Work

I use similar method, but with FG and XY octopus and oscilloscope. I use 10R, 100R or 1K resistor, with a 100, 1khz and 10khz frequency. It works very well to test capacitors and transformers in circuit. Even I can put DC offset. +10 to -10, and frequency to 0 to supply little circuits and view current consumption.



-----Mensaje original-----
De: [] En nombre de Bert Haskins
Enviado el: sábado, 16 de mayo de 2020 20:51
Asunto: Re: [TekScopes] Looking for a better in circuit ESR meter

On 5/16/2020 10:21 AM, Reginald Beardsley via wrote:
I'm using the website as my mailbox was getting swamped. I could make no sense of your ASCII art. Please get on the website and look at your own post. That's what I see.

I just ordered an EDS-88A II designed by Dave Miga from Merced Electronics. I'll see if it can successfully test the wad of caps that the BSIDE ESR02 Pro (aka Arduino LCR/transistor tester) and the Peak Atlas ESR70 cannot.

Both of those work for a lot of caps, but not for this tightly packed set of 12. They get reported as under 200 pF. Getting one back in after removal will be a huge pain. So I *really* want to be sure it's bad before removing one.

I'm trying to sort out a LeCroy DDA-120 which is misbehaving as if the front panel controls were intermittent. I suspect that I've got a noisy PS rail, but on an SMPS that's very hard to test because of ground access. I only have a few places I know of I can access the rails and no ground close enough to not have a huge problem with magnetic pickup.

1. !!!! Discharge!!!!! any/all caps.
2 connect scope and (F)unction (G)enerator ground to cap - / ground.

3. Connect function generator output to a 1K, 10k, or ? to protect FG output in case the CUT is shorted.

4 Set FG output to low.

5 Connect scope CH1 and the other end of the resister to the + side of the CUT.

6. Set FG to 1k, 10k, .. CPS and raise the output while watching the scope.

7 Keep the output of the FG ( as seen on the scope) to under .25 volts or so.

Needless to say, you can look at the FG output with CH2. and you will
now have everything you need right on the scope screen.

I have used this method for decades mainly as as sanity check in
conjunction with other methods.

Reply to this if you want to.

-- Bert

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