11 Jul
2007
11 Jul
'07
9:50 a.m.
On Tuesday 10 July 2007 13:54, Patrick Finnegan wrote:
On Tuesday 10 July 2007, der Mouse wrote:
There's no reason that you can't use a reverse-biased Si diode at its
breakdown (avalanche) voltage, as long as you kept the current to a
sane level (not a whole lot more than the current rating of the diode,
that is).
That's basically what a Zener diode is, anyways, just a silicon diode
with a precise breakdown voltage.
The main problem would be that a reverse-biased diode doesn't have the
same characteristics as a neon bulb... once you're back below the
avalanche voltage, it'll stop conducting in the reverse direction.
If you wanted to use something that was made of silicon, I'd suggest
using an SCR to do this. Use a zener or reverse-biased diode to set
the "turn on" voltage, and it'll turn itself off once the voltage gets
low enough across it.
Wow, I'm actually applying some of that "electrical engineering" stuff I
was taught in my undergraduate career. :)
Since a lot of parts like UJTs aren't ax commonly available as they used to be
I poked around some and found stuff online as to how one might "make" one
using a complementary pair of transistors. Couple each base to the other
one's collector, and you have an SCR, an SCS, or a PUT, depending on how
you wire it up. Not all that much difference between them... :-)
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
It's
an oscillator built around a capacitor and something with a
breakdown voltage, a neon lamp for example.
With a breakdown voltage, a (lower) extinction voltage, and such that
breakdown does not harm it (in contrast to, say, a reverse-biased
silicon diode, which would likely fry in such a circuit).