At 09:10 AM 2/21/02 +1100, you wrote:
>BC639  2N2222
>BC640  2N2907

Tony, do you recall what the maximum Pd is on those transistors?

The (metal case) 2N2222 is only good for 500mW at Ta = 25'C, the
2N4401 (cheap, ubiquitous) 630mW at Ta = 25'C, your BC639/40
for 830mW @ Ta = 25'C (burnt finger, anyone?)

Unless some are running quite warm, the 2N4401/2N4403 should work for
all of them, except that none of the pinouts will be correct, and
there are two variations. ;-)

If I was doing it with your PCB design and parts *I* had on hand, I'd flip
a 2N4401 or 8050 (US pinout) for the one part, and use 2SC1815/2SA1015 for
the BC639/640. Doesn't work for anyone else, I'll bet.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
9/11 United we Stand

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