Capacitors and Capacitance

This note focuses on the use of a capacitor. For the physics behind a capacitor, see Capacitance.

Capacitance

Definition

A capacitor is like a small battery which stores electricity. Capacitance is measured in farad (or commonly microfarads $µ$ )

Left: A polar capacitor
Right: A non-polar capacitor

Recall Ohm's law. The relationship between current and voltage is more complicated when capacitors or inductors are involved.

Definition

When a current passes through a capacitor of capacitance , the voltage drop across the capacitor is:

Recall . This becomes

Recall

Law