On Fri, 06 Jul 2007 01:13:34 GMT, J.P. wrote:

On Thu, 05 Jul 2007 23:06:47 GMT, qrk wrote:

On Tue, 03 Jul 2007 19:44:04 GMT, Eeyore
wrote:



"J.P." wrote:

http://alytus.auksa.lt/esr/

You posted this crap here too ?

Maybe some kind person will provide a circuit that works.

Graham

Yikes, that circuit might measure impedance, but surely not ESR. That
would be a good design for students to nit-pick for a homework
assignment.

HP4194 or HP4195 work great for ESR measurements. Got those two
instruments sitting next to me. Still need to build up the interface
boxes to the 4195! I think we have the schematics of both boxes too.

---
Mark
The guy that designed it repairs Tek scopes for a hobby and many have
been built and used successfully already...those hillbillies don't
have a clue...go to thr Yahoo Tek scope repair group and ask them if
you have any doubts...

It doesn't measure ESR, it measures a sort of twisted/nonlinear/offset
version of total impedance. It probably will tell open electrolytic
caps from good ones, but the thing the needle indicates isn't ESR. For
very big C's with low ESL (ie, when Z is mostly ESR, and low ESR at
that) then it mostly measures ESR.

For a similar level of complexity, one could measure true ESR. Or for
a lot less complexity, one could measure what this thing measures.

John