A transistor is a component that works as a current amplifier or a switch. When used as an amplifier, a small amount of current at one end produces a large amount of current between the other two terminals. When used as a switch, a small amount of current at one terminal opens up a gate for current to flow between two other terminals.
NPN transistors (like our NPN Transistor module) typically have three terminals:
- Base – your sort of “control” voltage. Current applied here affects what happens between the other two.
- Collector and Emitter – based on the input from your base terminal, current will flow from the collector to the emitter (essentially the output); Note that in some cases current can flow in reverse as well.