Brian Reay wrote in :

On 15/05/14 16:20, Custos Custodum wrote:



After studying (mainly BJTs, but with FETs in the final year) at
Uni,
I was conversant with all the models, Hybrid-Pi, etc, and the use
of various matrical parameters, h, y, s, etc, for describing and
predicting transistor behaviour in circuit, but was puzzled on how
it
actually worked, by which I mean, how did the base current control
the
collector current?

(So many of the textbooks just glibly say that the part of the
emitter
current
divides off to become the base current, but this does not describe
the
low-level controlling action)

I found the answer about 18 years ago in these NG (ISTR
sci.electronics before its unnecessary split), but I wonder whether
anyone else puzzled over this, and what was their answer?



It's all perfectly simple: holes are just electrons with negative
mass.

LOL

Actually, I wasn't kidding. (Well maybe just a little.) I've forgotten
most of this stuff in the 45 years since I studied solid state physics,
but ISTR that it was a useful theoretical device when analysing charge
carrier mobility or something like that.