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wrote:
Steve,
I built my own ESR meter using a function generator and a fluke DMM. I
set the generator to 10kHz and about 10V RMS. I then placed a 10k
resistor in series with the output so it will be sourcing 1mA RMS. Take
the other end of the resistor and the ground from the function
generator and connect these to your DMM on the AC mV range. The meter
should read overrange. Connect a 10 ohm resistor across the points and
adjust the output of the function generator until the meter reads 10
mV. Now your ESR meter is calibrated. Connect the two points across
various caps in the circuit. If you find any that read more than a
couple mV (Ohms), they are most likely bad. Note, a 1uF cap at 10kHz
should read 15.9 ohms, a 10uF should read 1.59 ohms and so on.
Scott

Clever. The high voltage means it isn't well suited to in-circuit. Any
reason not to use a higher frequency to minimize the affect of the
capacitive impedance? Most ESR meters seem to use 50KHz or 100KHz.

That's good though, clever, quick and dirty. Actually, if you put a
couple of shottkey (sp?) diodes across the leads, the output can't go
high enough to trigger a silicon junction but it shouldn't affect the
ESR reading.

Steve Greenfield