MIKE ROSS wrote in a message to Roy J. Tellason:

 MR> "Roy J. Tellason" bravely wrote to "all" (11
Dec 03  20:16:58)  ---
 MR> on the heady topic of "*big* transistors"

 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.
 RJT> There can't be _that_ many different types of numbers that use this
 RJT> package (no numbers are apparent on it,  though maybe cleaning them up
 RJT> a bit will help).
 RJT> Anybody care to guess as to what assumptions might be reasonable for
 RJT> these?
 RJT> I'll bet I can find something to do with them...   :-)

 MR> I can't find the ECG73 either. Perhaps it is a misprint?

Possibly,  but on the page where they show that sort of package it's the
only one with a 1/4"-28 stud except for one other that mentioned
"isolated stud" and which has slightly different terminals on it.
 This has two solder-eye terminals and one "hook" for the
collector,  so it's not isolated from the case.

 MR> IIRC that stud mount case style was seen in old GM-Delco radio 
 MR> hybrid tube/transistor as the final power out.

I thought they used a TO36 ("doorknob") case mostly?

 MR> The only thing I can suggest is to put a test unit on a transistor 
 MR> curve tracer that can drive those big babies to their voltage and 
 MR> current limits. Like... experiment with them! ;-) 

I have a curve tracer,  but I seriously doubt that it'll go anywhere near
either the voltage or the current limits.  Maybe voltage,  if these are LV
devices,  but it only goes up to 100V.

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