The whole point of a BJT is that it is driven by current, not
voltage. That current might be small but it is current never the
less because it is current that makes the transistor work. FETs
on the other hand are voltage devices and draw negligible
current apart from the initial charging of the gate source
capacitance. I never stated that a BJT could work without
current! I originally recommended using FETs over on the 3 mA
pins because I know the difference on how they operate. Lets
look at each in turn:- 1) Common emitter - the normal way I
would recommend, base current determines collector current 2)
Common base - note the page says this is not suitable for a TTL
voltage buffer, it has a low gain and typically I use this for
video coupling. 3) Common collector better known as an emitter
follower. - This has no voltage gain but a current gain, you do
not need a base resistor because of the feedback on the emitter
keeping the emitter / base voltage stable. However this is 0.7V
so this means when you use it a