Ingvar said:
Well, as you state in your paper "Despite much literature that
implies other wise..." I think it must be debatable, otherwise I
can't see that "much literature" would imply so
Its not debatable in the sense that it is accepted by any physicists
that understands how transistors actually work. Its simply impossible to
derive and sensible device equations on the assumption that base current
controls emitter current. The most simple derived equation is:
Ie = Io.(exp(Vbe/Vt) - 1)
Its called the diode equation. It is derived/shown in *any* standard
text book devoted to the device physics of the transistor. Its based on
applying a potential to the junction. There is no iffs or butts about
it.
Unfortunately there are rather a lot of non or semi technical books that
use explanations equivalent to water down a pipe. The sooner novices get
to grips with the fact that the ic=ib.hfe model, is a *grossly*
simplified model, with limited use, the better. It causes never ending
confusion.
From my point of view. If I feed 1mA into the base the Ic would be
some hundreds (hFE) mA (if available), even though I know that hFE is
not very accurate. On the other hand if I supplied 0.1V to the base,
nothing much will happen at the collector. I can accept that it can
be seen as a Voltage amplifier, but only around its working point (Vb
~0.6-0.7V).
You are looking at this from a way too naive point of view.
The transistor is a transconductance device. It outputs a current based
on its input voltage. It can be accurately exponential over 6 decades.
Sure, at low voltages, there is only a small current, but this doesn't
change how the transistor operates.
Its not a mater of what you want to accept. Its how it is. You can't
disagree with all the semiconductor physicista in the world, well not
unless your name is Einstein anyway-)
What I am explaining is *THE* *standard* *accepted* physics of the
situation. *Only* those *without* the academic background have
transistor operation mistaken. Go and have a read of *any* standard text
on semiconductor physics.
Kevin Aylward
[email protected]
http://www.anasoft.co.uk
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