I have some old capacitors I want to use in a simple bridge plus capacitor
PSU. They are marked "Dubilier Duconol 50uF 2500v Photoflash Made in England
TF".
I have searched the amps archives and note that folks suggest that derating
this type of capacitor to 50-66% of its marked voltage makes it OK for mains
PSU use. Why? Electrolytic capacitors are rated for ripple current, which
obviously translates to heat via ESR. What is the physics behind the
suggested voltage derating for oil filled paper block capacitors?
Oh, and once derated, how do I figure out how much ripple current they can
withstand, short of giving them some stick and risking a burst can and
spilled PCBs?
Should I just bin them and go buy ten new 450v electrolytics?
Alan G3XAQ
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