Sean Breheny wrote:
>
> At 11:58 PM 12/4/99 PST, you wrote:
> >    In present day terms, does a "source" provide conventional current
> >    or does it provide electrons?  Same for a "drain" ... does it drain
> >    conventional current or drain electrons?
> >
> >Um, I don't actually recall.  Most of our FETs were theoretical and fairly
> >symetric, too, I think.  I don't recall ANYONE ever justifying the names of
> >semiconductor terminals.  Hmm.  I can dig "Solid State Electronic Devices"
> >(Streetman) off my shelf, and lookup the chapter where FETs are
> >introduced:
> >
>
> Hey Bill, we still use Streetman's book (a newer edition). I just thought
> it was interesting to see you mention his name :-)
>
> Also, in my courses, we always use conventional current, even in the
> Physics courses. I think that the names of semiconductor terminals refer to
> carrier movement. SO, in a FET, the source is the electrode which supplies
> the charge which will be carried by the majority carriers, and the drain is
> what accepts the carriers. In BJTs, the emitter supplies the charge which
> will be transported by the carriers. These do seem to be rough names, though.
>
> Sean
>
> |
> | Sean Breheny
> | Amateur Radio Callsign: KA3YXM
> | Electrical Engineering Student
> \--------------=----------------

Thanks Sean ... You've put me on the right track as to how to explain it
to my two sons that I'm home-schooling in electronics.  Unless somebody
has a reason to do otherwise I'll have them think in terms of
conventional
current flow (which is the opposite of electron movement), that the
terms
drain and source are applied to the carriers which may be electrons or
holes.

One last question:  In the symbols Vdd and Vss, what do the "dd" and
"ss"
subscripts stand for?

 - Nick -