[Milsurplus] Leakage in Electrolytics

J. Forster jfor at quik.com
Sat Oct 22 21:25:22 EDT 2005


Don Davis wrote:

> Not really.  DC leakage is dc, and the voltage is dc.  This is the resistive
> portion of the capacitor in shunt with the capacitor.  It is strictly an E x
> I function.    My opinion:  2 mA is excessive, and the cap is worthy of
> replacement.

2 ma is the leakage. It's DC. So is the applied voltage. That's the dissipation
we were discussing. NO phase angle involved.

It has NOTHING to do with ESR, and I know EXACTLY what I'm talking about.
Furthermore, the dissipation due to ESR is I*I*R, where I = RMS current through
the C and R is the ESR. It has NOTHING to do with the voltage across the
capacitor. NOTHING.

-John


> In addition, there is an ESR (Equivalent Series Resistance) that will
> dissipate due to an ac current flowing through the capacitor.  It is an
> I(ac)**2 x R x cosine(o) factor.  This is probably what you're thinking of.
> Can also be very large, and lead to early failure.
>
> Don  AD6PB
>
> ----- Original Message -----
> From: "James Duffer" <dufferjames at hotmail.com>
> As I recall there
> > is a phase angle between capacitor current and the voltage producing the
> > capacitance current.  watts=I x E x PF.  Power Factor (PF) being the
> cosine
> > of the phase angle.  We can't forget Eli the Ice man.
> >
> > 73, de wd4air





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