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

 -=> Roy J. Tellason said to All
 -=> about "*BIG* TRANSISTORS" on 12-11-03  20:16.....

 RJT> Got some fairly hefty transistors here,  stud-mount package with a
 RJT> 1/4"-28 stud on the bottom of the package.  The ECG book I have here
 RJT> handy calls that a "TO61" package,  and they list a
variant with an
 RJT> isolated stud (which this is not),  and the version I have is called
 RJT> out for ECG73,  which does not appear anywhere else in the book.

 GM> I haven't seen transistors like that for about 40 years. But a lot
 GM> of SCRs use that package.

 RJT> There can't be _that_ many different types of numbers that use this
 RJT> package

 GM> HA! I wish.....

 RJT> Anybody care to guess as to what assumptions might be reasonable for
 RJT> these?

 GM> Yep. For my money they are SCRs.

I don't think so,  but let's see what an ohmmeter has to say about it...

Nope.  Reads like an NPN transistor,  with the pin that's common to the
case being the collector,  I'm guessing.

 GM> But IMO doing some tests will be the only way you'll find what they
 GM> are, and even then ratings will be purely guesswork.

 GM> Unless of course you can find their part numbers.

They're pretty dirty,  I need to figure out something I can clean them with
that won't affect any numbers that might be on them.

 RJT> I'll bet I can find something to do with them...   :-)

 GM> Yup, once you know what they are ;-)

Bet they'll carry a bunch of amps,  at least...

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