18 Jun
2011
18 Jun
'11
10:19 p.m.
On 18 Jun 2011 at 23:39, Charlie Carothers wrote:
Any idea if that was due to their mechanical
construction? I recall a
computer system in the early 60's that was plagued with diodes that
would sometimes open up with the slightest vibration. Then in the mid
60's I worked on an optical character reader with many more diodes but
nary a problem with them. I seem to recall the latter ones being
referred to as having "unitrode" construction, which could be my
faulty memory, or perhaps that was a TI term as we were using their
diodes extensively in the OCR system. Later, Charlie C.
1960's diodes were very different from 1950's. Here's a shot of a
1N34:
http://www.radiomuseum.org/tubes/tube_1n34.html
You can see the "cat whisker" construction in the lower right corner.
You can see the construction quite a bit more clearly in this shot of
a 1N21 silicon microwave mixer diode:
http://www.radiomuseum.org/tubes/tube_1n21a.html
Delicate mechanically, and with a current limit of 5 ma, very easy to
destroy. Also, the characteristics diode-to-diode were far from
uniform.
Still, for the postwar hobbyist, the 1N34/1N34A was "the" diode to
use.
--Chuck