When a voltage is applied across a capacitor, the orbits of the electrons in the
dielectric are distorted by the electrostatic field which exists between the charged
plates of the capacitor. See figure 1.
The better the insulating ability of the material used as the dielectric, the greater the
voltage we can apply across the capacitor without the dielectric breaking down or
arcing through. A better insulator permits use of a stronger electrostatic field,
resulting in a higher capacity.
The fewer free electrons there are in a material, the better is its insulating
The definition for the term dielectric constant is: A MEASURE OF THE ABILITY
OF A MATERIAL TO SUPPORT AN ELECTROSTATIC FIELD AS
The symbol for dielectric constant is