"Phil Hobbs" wrote in message
...
On 02/16/2017 12:46 PM, Clifford Heath wrote:
On 17/02/17 09:03, Dave Platt wrote:
I was repairing a piece of old equipment, and needed a replacement RF
transistor. Checking at Digi-Key, I found very thin pickings, so i
checked
a few other distributors, and found the same situation. They seemed
to have
a modest choice of SMT transistors, but REALLY thin variety in T0-92
and
similar plastic packages. Not a good sign, as we have a lot of 30 -
40 year
old nuclear instrumentation here.

Yup. The last five years or so have been dire times for through-hole
semiconductors. A lot of the popular parts are now gone, past the
end of the "lifetime buy" cycle from their original manufacturers.

I've been trying to stock up my own (hobbyist-level) supplies of
useful TO-92 transistors...

Why? You're not doing production if 100 is lifetime. If it's for
prototyping, why not just learn to prototype in SMT? It's not that
hard. A lot of RF things are easier because stuff is physically
smaller.

SMT prototyping is about a factor of 10 slower than dead bug using
through-hole parts. Every DIP package gets you a bunch of nice strong
standoffs.

I regularly include SMD parts in dead-bug prototypes. With a bit of thought
and planning they can reduce wire links instead of increasing them, they
also tend toward adding rigidity to the assembly.