Re: Current - vs - Voltage


"Scott Brehler" <sbrehler@xxxxxxxxxxxxxxx> wrote in message
news:lb58i.17192$j63.8813@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi all,

This has been burning in the back of my mind for quite some time, and I've
not been able to come up with an obvious/simple answer.

What is the difference between something being described as voltage
controlled as opposed to current controlled? I.E. FET's(voltage
controlled) - vs - BJT's(current controlled). If current and voltage are
directly proportional to each other (given a constant resistance)why is
one
device described one way and the other another way? It seems that you
could
always use voltage (or current) to describe either device and come up with
the same calculations.
Is it because the resistance of the device is variable that one is used
instead of the other? I refer to the transistors, but I've heard of other
devices described as current controlled or voltage controlled too. What
makes this distinction?

Thanks in advance for any input.

Scott



Thank you for the GREAT replys. I had sneaking suspicions, but wasn't able
to put it quite so elegantly as those of you. I am greatly enlightened now!

Scott


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