First off, let me say that I've read a couple books at this point, and I'm pretty sure I understand most of the basics, but I'm having an issue with something: FET polarity. So, we'll come back to that. First, let me make sure I understand here.
In my mind, using the stereotypical water analogy, a transistor (bipolar) is kind of like a syphon. A signal comes into the base, and continues on through the emitter pulling extra current from the collector. So, if you marked an electron that was coming into the base, you could see it come out of the emitter (I think). I still don't quite fully understand bias, or NPN vs. PNP other than it flips the way the transistor works. I also understand a transistor is current driven. But obviously there needs to be a voltage to drive that current...
A FET, on the other hand, is like a valve. The voltage on the gate controls that valve (and if it's NPN, it's normally off with 0V on the gate, or if PNP, it's on with 0V). And my understanding is when it's on, a current flows from drain to source. Anyway, if you marked an electron on the gate, you'd never see that electron come out of the source, or drain. I also understand FETs are voltage driven.
But I also understand that FETs really aren't polarized, so current can flow both ways, yes? Transistors are polarized, yes? Is this only due to the fact there's a higher voltage on the collector? I know you get avalanche breakdown (which depending on the transistor, this can be destructive or not) when you push the wrong way through a transistor, but I'm not sure that's entirely relevant to the conversation. Which leads to my confusion...
What's the point of having a source and a drain if they're non-polarized? Is it just for signifying what the gate bias is relative to (source or drain)? Anyone have a good reference for any of this? Mnemonic? Anything? If I could get my head around this, I think I'd have an easier time... at this point, I'm just having to look at a schematic, and figure out which way makes the most sense for things to be (like a stereo receiver I'm working on, where the mute function is two transistors that pull the signal down to ground).
Again, please correct me if any of this is wrong... or elaborate if possible.
Thanks!