Hi,
I've had an agonizing time figuring out how transistors work, and the puzzle is finally starting to come together. But one major source of confusion that has befuddled me the past few days is how to understand the logic behind the symbols of BJT and MOSFET transistors.
NPN: POSITIVE base causes current to flow from collector to emitter. Symbol is arrow pointing OUTWARDS, WITH current flow
PNP: NEGATIVE base causes current to flow from emitter to collector. Symbol is arrow pointing INWARDS, WITH current flow
Nice and simple. Now, suddenly, here's MOSFETs:
N: POSITIVE gate causes current to flow from source to drain. Symbol is arrow pointing INWARDS, AGAINST current flow
P: NEGATIVE gate causes current to flow from drain to source. Symbol is arrow pointing OUTWARDS, AGAINST current flow
So not only have the N's and P's "swapped meaning", but the symbols also don't seem to follow the same logic. I'm sure those symbols had a long way through several committees before being accepted, so what's the reasoning here?
Or maybe I've confused them once again..