[Amps] Blocking capacitor drift

[jeremy-ca]

----- Original Message ----- 
From: "Peter Chadwick" <g3rzp at g3rzp.wanadoo.co.uk>
To: <amps at 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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