>
> Is there any easy way to measure the ESR (equivalent series resistence)
> of a given capacitor?
> By the way, this IS a PIC related question!

Take a siggen, output impedance 50 ohms, set it to sine wave, output 5V
connect across cap, now, with a scope, now look at the voltage across
the cap with a scope.
Reactance is shown by voltage across the cap, .1V= 1 ohm reactance
this only works when 1/6.28*F*C (f= freq, C = capacitance in farads)
is quite a bit less than the ESR.
A quick and nasty way is to use a square wave on the siggen,
increase frequency till you get a fairly good triangle wave at small amplitude
now, a perfect capacitor will just give a (bit distorted, but good if the
amplitude is low) triangle wave, but, if you put a resistor in series you
will get a wave that looks like a triangle wave, but with the sloping bits
not lining up properly, now, look at the top end of one of these waves
it'll be something like

 /
/
  \
   \

approximately, the discontinuity will reflect the ESR, quite accurately if the
voltage is small, if it is, the siggen can be thought of as a current source,
and the discontinuity will be V=IR where V= peak-peak siggen output, R =
ESR of capacitor, and I = V/siggen output resistance


>
> Regards,
>
> Octavio
> --
> ========================================================
> Octavio Nogueira
> e-mail:   nogueira@mandic.com.br
> homepage: http://ourworld.compuserve.com/homepages/tato
> voice/fax: +55 11 240-6474
> "ProPic" The first Production PIC Programmer running in
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> ========================================================
>


--
Ian Stirling.                        |  http://www.mauve.demon.co.uk/
AKA Caeser, Bolonewbie.              |  With information on the PDA I'm making.