16 Aug
2005
16 Aug
'05
3:55 p.m.
Back in college, I took electronics for non-EE
majors. The first half of
the course dealt with analog electronics (including the analog
characteristics of transistors) and while most of the other students had an
easy time with that portion, I struggled hard and I *still* don't quite
understand the operating characteristics of a transistor, or what exactly
the difference is between a PNP and NPN transistor.
Basic difference : polarity of all the voltages. For an NPN transistor,
the collector is +ve wrt the emitter, the base is baised towards the +ve
supply too. For a PNP transistor, the collector is -ve wrt the emitter, etc.
In fact, if you take a circuit using an NPN transistor, reverse the supply
polarity, the polarity of input and output signals. and any polarised
components (diodes, etc), then put a PNP transistor in of the same
characteristics, it should do much the same thing
Do you have Horrowitz and Hill 'The Art of Electronics'? If not, buy it.
If you do have it, read it :-).
Second half the course though, was digital electronics which I found
trivial, although most of the other students had real difficulty with the
concept of +5V being a logical 1 (what? 5 = 1? What? What the hell are
you talking about?) and the less said about Boolean algebra, the better 8-P
And if programmer can't grasp the difference between equality and
assignment, then heaven help us when you get to pointers ...
I'm no programmer, which is probably why I had no problem with the
differnce between equality (means a test with an XOR gate) and assignment
(means a load into a D-type) :-). And pointers didn't worry me either.
Thing is, I understood the PDP11/45 microcode before I tried to learn C...
-tony