Now that we understand what the 555 is, and how it operates, it's time to explore what it can be used for.

The 555 has 3 basic modes of operation:

1. Monostable/one-shot: The trigger input is used to make the output high for some amount of time, after which is goes low until it is triggered again.
2. Astable/free-running: The output switches between high and low at a specific frequency and duty cycle.
3. Bistable: The output is controlled by two inputs. This basically just exposes the internal flip-flop.