do ployprop caps age?

[george a]

Hi All

I have some old (20yrs) polyprop capacitrors (Rifa) and I'm wondering if this type of cap ages and if how and to what effect.?

These were originally used as xover caps and am loking to use them again. (i know they work at least in some capacity.
Any comments appreciated,


regards

[rcavictim]

If they aren't shorted go ahead and use them. Polypropelene caps don't *age* with time like wax and paper caps did (and that problem is mostly related to the infiltration of moisture). Poly caps do age with use in impulse energy discharge applications but those extreme dielectric stresses are not seen in amplifier use or in a crossover, or with sitting on the shelf.

OTOH, if they were stored in a box sitting next to the business end of a particle accelerator in a nuclear laboratory, don't use them.