> You're assuming wrong - bipolar transistors are voltage amplifiers - if it
> has a gain of 100 and you put 5 volts to the base in theory it would let
> 500V pass (but most 'normal' transistors can only handle moderate
voltages -
> around 40-60).

Bipolar transistors are current amplifiers.  The collector-emitter current
allowed by the device is roughly the base-emitter current times a "gain"
factor.  Of course there's a lot more to the behaviour of a bipolar
transistor, but this is the main characteristic motivating their use in most
applications.

If you're new to this sort of thing, you can get some useful work done by
thinking of the model above, with the addition that a forward biased base
looks like a diode with the accompanying voltage drop (figure about .6 to .7
volts for silicon).


*****************************************************************
Olin Lathrop, embedded systems consultant in Devens Massachusetts
(978) 772-3129, olin@cognivis.com, http://www.cognivis.com

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu