dual complementary transistors

"steve marchant"

PNP plus NPN pairs on the same chip are rare as hen's teeth - cos is is near impossible to make good devices in both polarities that way.

Dual transistors in PNP and NPN are common, as that is the way to get excellent device matching for diff pairs et .

For a complementary pair, for switching applicatons - for heaven's sake use TWO devices.

How about BC639 and BC640 - glued together if you like ??

..... Phil

At the time when this design was popular, using two transistors on the same substrate ensured they were more closely matched than any old two separates from a bin.

I knew associates who bought many, and sat with a transistor tester for hours to find close matches.

Today, you wouldn't do it anymore, there are better ways of doing just about everything. But if you're in the repair game, you might not have the luxury, funds or time to re-design from scratch...

"John Tserkezis"

F****IT !!

" PNP plus NPN pairs on the same chip are rare as hen's teeth - cos is is near impossible to make good devices in both polarities that way. "

.... Phil

I never claimed I read any of your posts before snipping Phil.

"John Tserkezis Wog IDIOT "

Either way - nothing goes in to your impenetrable, autistic skull.

..... Phil

Now, now Philthy. Calm down, make a good strong cup of tea and take a stress pill.

"Alan Rutlidge"