12 Feb 19

Examples of dielectric media are glass, air, paper, plastic, ceramic, and even a semiconductordepletion region chemically identical to the conductors. From Coulomb’s law a charge on one conductor will exert a force on the charge carriers within the other conductor, attracting opposite polarity charge and repelling like polarity charges, thus an opposite polarity charge will be induced on the surface of the other conductor. The conductors thus hold equal and opposite charges on their facing surfaces, and the dielectric develops an electric field.

A simple demonstration capacitor made of two parallel metal plates, using an air gap as the dielectric.

Source: Wikipedia