----- Original Message -----
From: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
To: <amps@contesting.com>
Sent: Sunday, September 30, 2007 9:29 AM
Subject: [Amps] Blocking capacitor drift
> My experience with ceramic caps of this sort is not so much drift in
> capacity as apparent upwards drift in loss. Even if a coupling capacitor
> did drift in capacity, as Tom points out, you wouldn't really notice. Loss
> is another matter, especially for padder capacitors carrying a lot of
> current. If you keep the juice on for long enough, all sorts of
> interesting things happen, usually, I find, with bits becoming unsoldered
> internally, and the thing falling apart with a smell of burnt paint, a
> few arcs and flashes and bangs and hopefully, the breaker or fuse pops
> before you have an expensive tube damaged.
> The other point is that at least in my experience, once a ceramic cap
> decides to start getting hot, that's it - it is at the end of its life.But
> very often, I've found, at low current levels, it appears fine, so
> measuring on a Q meter may not show a problem.
> 73
> Peter G3RZP
We are on the same page Peter.
Carl
KM1H
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