Hello :-) I can't seem to get a good understanding about a part of transistors and how they act. What I think I know about transistors now is as follows: They're made up of npn or pnp called emitter, base and collector, and the junctions between them are emitter base junction and collector base junction. I'm going to use an npn transistor as an example, by the way. The emitter is heavily doped so it can give off many electrons, the base is thin and lightly doped so many of the electrons from the emitter can flow through to the collector which is less doped than the emitter. A voltage is applied between the emitter and the base, with the catode directed toward the base so the electrons pass through the depletion region at the emitter base junction. Here is where I'm stuck: Then a voltage is applied between the emitter and collector? Why? And in which direction does the current flow? Does the voltage between E and C need to be sufficient to get the electrons past both the eb junction and the cb junction?