Claude,
Yes, I am aware of inverse relationships. My point is that Vbe and Ic are tied together by a relatively simple equation that does not involve QM to express. I iterate that I would not design a BJT using that equation, however.
I don't agree that Ib & Ic change before Vce. I would think they changed together. You are right, I cannot imagine one of those variables changing before the other.
The one I referred to earlier. Here is his website.
**broken link removed** . He responded to me with a email when I asked him if a BJT was CC.
Ratch,
I hate to be the one telling you this but the BJT is indeed a voltage
controlled device. The voltage applied to the base emitter junction controls
the collector current and the base current is a result of the additional
hole injection (for an npn BJT) into the emitter as well as the
recombination in the base-emitter depletion region and the quasi-neutral
base region. It is tempting to claim that the BJT is controlled by the base
current, since that is how a BJT is typically biased; the exponential
variation of the current with the base-emitter voltage makes a voltage bias
impractical. Any circuit designer will also tell you that any voltage bias
can be replaced by its Thevenin equivalent current source. Hopefully this
provides you some ammunition to claim that either one can be claimed when
treating the device as a black box. Finally, you'll find that a MOSFET
biased in the subthreshold region has characteristics that are very similar
to that of a BJT.
Bart Van Zeghbroeck
Professor
University of Colorado
Department of Electrical and Computer Engineering
Campus Box 425
Boulder, CO 80309-0425
Office ECEE1B41
Tel: 303-492-2809
Fax: 303-492-2758
Email:
[email protected]
The ME you referred to was off base, of course.
No, I do not.
Yes.
I agree it does. And if the BJT has a higher β, then it requires less energy, less current, but the same Vbe.
Certainly they can.
Ratch