An Absolute Beginner With A Few Questions

[Rich Grise]

Bah. That bit's always confused me, and I *thought* I'd looked it up
and verified it the other way round. "Collector" just seems the right
term for collecting all the current. Oh well. Stupid transistors.

It does. In an NPN transistor, it collects electrons, and in a PNP, it
collects holes. ;-)

Oh! I see your confusion! The emitter current is the sum of the base
and collector currents, but you seem to have had the impression that
"collector" implied that the collector current would be the sum of the
base and emitter currents? That's OK, and not a hard mistake to make
first time out. Don't worry - it gets lots easier with a little practice.
I guess you could say that the collector collects whatever didn't
get diverted to the base. Historically, it's called the base, because
it was literally the base - like those galena crystals with the cat-
whisker - and the emitter and collector were two cat-whiskers. (or
maybe safety pins. ;-) )

Cheers!
Rich

 

[Michael A. Terrell]

electrical energy doesn't always flow from positive to negative, else how
would AC appliances operate?

It is traditional to use a positive supply and negative ground in many
designs (especially digital) but as you noted "communications" equipment
(telephone?) uses positive earth.

Bye.
Jasen

What in the world are you talking about? Electrons always flow from
negative to positve. When the power source changes polairity, it flows
they other direction or it wouldn't be "Alternating Current">

 

[John Fields]

electrical energy doesn't always flow from positive to negative, else how
would AC appliances operate?