29 Jun
2012
29 Jun
'12
9:57 a.m.
On Jun 28, 2012, at 9:28 PM, Mouse wrote:
You're correct in your understanding of ESR; it's basically a measure
of how much the cap deviates from an ideal cap. Most ESR meters are
designed to measure with short pulses so they don't charge the cap
overly much (which is why it's hard to do with a multimeter), and
they're usually designed to work in-circuit.
Wikipedia's page on ESR meters is a decent writeup.
- Dave
It's
possible to measure ESR with a sine wave signal generator and a
;cope [...]. It gets boring fast, which is why there are ESR meters.
I would tend to think - perhaps na?vely - that ESR is based on
considering a capacitor as an ideal capacitor in series with an ideal
resistor, in which case an ordinary ohmmeter could be used to measure
ESR, provided the current it runs through the "resistance" under test
is low enough that the cap does not charge significantly during the
measurement.
Do I misunderstand? Is there more to ESR meters than just working
around the "cap charging while measuring" issue?