If a negative charge flows left, then a positive charge appears to
flow right. Yes, only the electron "physically" moves.
That's halfways right, but I still just don't see the need of even
talking about the motion of positive charges. Talking about motion of
negatively charged electrons is enough in electronics.
Why only halfways right? Because it works only for a continual flow of
charges. If a continuous current flows, with a certain number of
trillions of electrons passing each spot of the wire in every second,
then it works fine to think in terms of the same number of positive
charges moving in the other direction. But if a single electron moves
through space, in a tube, and takes a while to arrive, how do you make
the equivalent with "conventional" current flow? You make a positive
quant jump out of the plate, and arrive at the cathode A LITTLE WHILE
EARLIER?
If you are travelling west on the highway, it's the same as saying that
a negation of you is travelling east, right? That works at the moment
when you and your negation meet, but not an hour earlier or later in the
trip!
In chemistry, yes, you can have motion of ions, carrying a current, and
these ions can have positive or negative charge. So it's true that
electric current is the flow of electric charges, which can be positive
or negative ones. But in electronics it's simply more practical and
intuitive to think in terms of the physical motion of electrons, than in
the opposite motion of abstract positive charges.
And about zeners and avalanche diodes, I have seen many datasheets that
correctly identify the higher voltage devices as avalanche diodes, and
don't use the name "zener". Even so the error is widespread enough.
Manfred
========================
Visit my hobby homepage!
http://ludens.cl
========================
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|