A capacitor is an electrical device which can be used to store a charge by application of a voltage. The simplest type of capacitor consists of two parallel plates with a voltage applied across them. A capacitor is characterized by its ratio of charge stored to applied voltage, called the capacitance and measured in Farads.Unlike a battery, when the voltage is removed, the capacitor discharges.
The voltage V across a capacitor with charge Q and capacitance C is given by

The potential energy stored in a capacitor is given by



The impedance of a capacitor is given by

The charge stored by a set of capacitors in parallel is given by

so it therefore follows that

For capacitors in series,

It therefore follows that