[AMPS] Re: PS diode equalizing

[Peter Chadwick]

Roy says:

>FYI, the ARRL Handbook warns never to use SILVER micas for HV DC
>service, as the silver tends migrate causing possible cap deterioration.


I was thinking in terms of stacked foil and mica, rather than silver mica.
ARRL aren't totally correct there; it depends on the capacitor. If humidity
can get in, you can get a problem with some of them. It can't be that much
of an inherent difficulty, or there'd be a lot of 4CX series tube sockets
with problems! I also know of an awful lot of military gear that has used
silver mica with dc across it without a problem. Some manufacturers derate
for RF volts, which could explain it - one manufacturer has a 350vdc, 50vac
rating - whether or not that's simultaneous, I don't know. Similar
limitations appear with polystyrene caps as well.

But obviously, the tolerances of the capacitors needs checking.

73

Peter G3RZP




--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm