Greg Mayman wrote in a message to Roy J. Tellason:

 -=> Roy J. Tellason said to Mike Ross
 -=> about "*BIG* TRANSISTORS" on 01-03-04  12:06.....

 RJT> You can turn an SCR off.  Just gotta hit it right...

 GM> But you gotta hit it hard, usually as hard as the load current it
 GM> is carrying!

Oh?  What little experimentation I did with that involved two of them, 
with a 100nF cap connecting the anodes.  When one was on turning the other
one on would turn the first one off.  Load was something like a light bulb,
 I think (it's been a while).

 GM> These devices which I believe were also called Gate Controlled or
 GM> Gate Turnoff Thyristors could be turned off by shorting the gate to
 GM> cathode.

I've heard of them.  Not for a long time though.

It's kind of interesting to consider an SCR (or SCS for that matter) as a
pair of cross-connected complementary transistors,  and in fact I'm
thinking about implementing some that way.  Then I get to pick the specs. 
  It'd be cheaper for me to do it that way since I have all sorts
of salvaged transistors around and wouldn't have to go out and buy
anything.

Too bad I don't have complements to those big stud-mounted ones...   :-) 

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