# Electrical Capacitance

A capacitor is a device that stores electrical potential energy and electric charge. Electrial capacitance is related to its ability to store the electric charge.
​If some charge is given to a conductor, then it is raised to some potential. The potential of the conductor increases as we increase the amount of charges. Let charge q is given to a conductor so that its potential rises through V. Then, $q ∝V$ $q = CV$ The proportionality constant C is called the capacitance of the conductor. It does not depend upon the material of the conductor.
It depends upon;
1. Shape and size of the conductor.
2. Relative permitivity or dielectric constant of the medium in which the conductor lies.
Capacitance of a conductor is defined as the ratio of the charge on it to its potential due to that charge. $\text{If V=1, then,}$ $C=q$
Thus, capacitance of a conductor may also be defined as the charge required to raise its potential through 1 unit.
The SI unit of capacitance is Farad (F) and its CGS unit is e.s.u. $1\text{ Farad (F)}=\frac{1 \text{ Coulomb}}{1 \text{ Volt}}$
Thus, if one coulomb of charge raises the potential of a conductor through one volt, then, the conductor is said to have one Farad of capacitance.