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[AMPS] Suppressors, measurements, and acrimonious blather

To: <amps@contesting.com>
Subject: [AMPS] Suppressors, measurements, and acrimonious blather
From: Peter_Chadwick@mitel.com (Peter Chadwick)
Date: Mon, 7 Aug 2000 09:15:19 +0100
Fred said:

        > I remain convinced, however, that a carbon composition resistor will 
        >change in value over time even if it is not heated.

Having inherited my fathers junk box, as well as having built up mine over the
last 40 years, I too have a number of brand new, never used carbon composition
resistors. Measurements indicate exactly the same thing that Fred found - they
have gone high. I have some 'High Stability' carbon comp resistors that are over
40 years old, and have been used; they're still within the tolerance rating. I
even found a few ordinary carbon comps which were still in their 1970's military
packaging, and they'd gone high, too.

It appears that 'ordinary' carbon comps drift high. 'High Stability' ones seem
OK - they have a pink band on them as well as the normal colour code for value
and tolerance. But I've never seen any 2 or 5 watt high stability ones. 
Now I also have from father's junk box some 5 watt solid carbons that are about
2 inches long and 5/8 inch in diameter, dating back to WW2. They are still in
tolerance............

I ought to check some of the carbon film ones I have - I know some of them have
never been used, and are 30 years old.

73

Peter G3RZP


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