23 Dec
2007
23 Dec
'07
3:38 p.m.
On Sunday 23 December 2007 18:02, Tom Watson wrote:
I suppose you could simulate them with a connected
PNP/NPN transistor pair
(as mentioned here), or use a higher voltage to trigger and use an SCR
(another 4 layer device) and not connect the trigger lead. These went out
of style long ago I understand. In looking things up, I ran across this:
http://www.allaboutcircuits.com/vol_3/chpt_7/3.html
which explains things in great detail.
That page with the two-transistor equivalent reminded me of this one:
http://www.4qdtec.com/putpr.html
which strikes me as a handy thing to be able to do, take a couple of ordinary
bipolar transistors and use 'em as an SCR, a PUT, a 4-layer diode, an SCS,
and all sorts of other stuff. :-)
--
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