Capacitors allow for the buildup of electrical potential, and then release it when it gets to a set amount. Capacitors can be fixed, in that their capacitance is fixed to a certain number, or variable which can change depending on inputs or physical changes. These are generally polarized, in that it’s important to pay attention to which side goes into a circuit.

Capacitors are generally marked on the outside what their values are.

On a circuit diagram, these are the symbols you will see.

Capacitor symbols