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Re: Cap AC voltage ratings
> Sure, ANY corona (partial discharge mail) will degrade the dielectric
> and should be avoided as much as possible. However, a degradation
> of the dielectric should (or am I making a mistake, here?) show up as
> a loss of capacitance.
I think the C will remain the same, but the loss or leakage current might
increase, and the breakdown voltage will decrease. Here's why: The failure
is a tiny pinhole in the dielectric, which is a very small part of the
total plate area. Therefore, the C will remain basically the same. However,
that tiny hole provides a place for future failures to occur, if only
because of the field distortions in the dielectric due to dissimilar
materials (dielectric and whatever fills the hole). The fault may also
manifest itself as a high resistance in parallel with the cap (i.e.
leakage).