[Boatanchors] copper cap rectifiers

[Glen Zook]

Actually, a germanium diode can be used under certain
circumstances as an approximately 0.3 volt zener and a
silicon diode can be used as an approximately 0.7 volt
zener.

A "trick" for low voltage regulation with a simple
circuit is to put series zener diodes from the base to
ground of a power transistor like a 2N3055.  You will
get approximately 0.7 volts with one "normal" silicon
diode, 1.4 volts from 2 silicon diodes, 2.1 volts from
3 silicon diodes, etc.  Just run the source voltage in
the collector and out the emitter.  This is often done
by antique / vintage radio collectors who are looking
for 1.5 volts and 2.0 volts for filaments.

However, a "normal" silicon rectifier doesn't usually
make a good zener.  But, in the above mentioned
application they do a pretty good job.  What you are
using for the "zener" function is the inherent voltage
drop across the junction.  Something like even a
1N4001 (50 volt PIV, 1 amp silicon rectifier) work
fine when used in the simple voltage regulator
circuit.

Glen, K9STH


--- WBob <wolfbob@csnsys.com> wrote:

Well that isn't too true.. All silicon diodes will
zener at about 2 or 3 x their voltage ratings.

=====
Glen, K9STH

Web sites

http://home.attbi.com/~k9sth
http://home.attbi.com/~zcomco

__________________________________
Do you Yahoo!?
The New Yahoo! Search - Faster. Easier. Bingo.
http://search.yahoo.com