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[Amps] Mica capacitors - Round 2

To: <amps@contesting.com>
Subject: [Amps] Mica capacitors - Round 2
From: philk5pc@tyler.net (Phil Clements)
Date: Sat, 25 May 2002 17:17:03 -0500
> >First of all, just exactly what does it mean for a capacitor to have a
> >current rating? I can already see signs of opinions lurking out there that if
> >you accidentally run 8.6A through your blocking cap rated at 8.5A, there will
> >be a meltdown of your beautiful 4cX00000000 amplifier.

One would assume from experience with other electronic devices
that if a cap is rated at 8.5 amps at a certain frequency that there is
headroom built in so that 8.5 amps can be applied continuously
for many years between failures, and that 8.5 amps can be exceeded
within reason for brief periods without damage.

The headroom for ceramic and mica must be very liberal, as
thousands of those TV-type non-RF rated doorknob caps are
still bypassing, padding, and blocking away. A good portion of these
were probably resurrected from a dumpster behind a TV shop.
What finally does these door knobs in is that hams have upgraded
over the years from 811A's to tubes with handles. As Rich and I have
found out, there is a limit to how far you can push even large RF rated caps
as you ease up the QRO ladder.

I appreciate the ratings printed on components. At least it gives
me an idea of how many to solder in series/parallel.

(((73)))
Phil, K5PC




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