Re: Where are all the ESR meters?

On Mon, 23 Jul 2007 09:09:26 -0400, Spehro Pefhany
<speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx> wrote:


I'm thinking of using a 2-volt peak sine wave with a 200-ohm

2-volt P-P is too high to do in-circuit testing in all cases as it
could cause Si junctions to conduct. 0.2V or 0.3V would be a lot
better.

10 mA won't make much voltage across an electrolytic cap!

Some of the designs out there don't bother with discharging the
capacitor- they put a low (and stable) -ESR cap of a few uF in series
with the DUT. That way you have an upper limit on the energy to be
handled (given an upper limit on the voltage of (say) 400VDC or 500VDC
to handle off-line filter caps).

The other possibility is to just limit the current, not instantly
discharge the cap,

John

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