From: John Woodgate
Subject: Re: Little metal diodes
Date: Wed, 2 Oct 2002 23:07:49 +0100
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Thu, 3 Oct 2002 05:53:09 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that N. Thornton
wrote (in ) about
'Little metal diodes', on Wed, 2 Oct 2002:
>Those would be modern (relatively) semiconductor diodes, from the 70s.
>Metal diodes have been around at least going back to the 20s. Theyre
>in plastic packs, maybe 1/4" across, 1/2" long, with type number
>stripes (I forget the number).
Are they in ceramic tubes? Nearer 3/8 diameter than 1/4? I think you
have selenium 'Unistors', asymmetrical resistors or mediocre diodes
depending on type and how you use them. IIRC the stripes don't use the
resistor colour-code, e.g. orange-orange-orange is not 'type 333'.
>I cant help wondering if one could actually use them in low speed low
They probably were so used originally. I used them only once, as catch
diodes in an amplitude-stabilized astable with a 12AT7 double triode, in
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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