Question

Why insulator is used in capacitor?

Answer 1

Capacitor: A capacitor is a device that is used to store the electrical charge on its plates by applying a potential difference across its plates.

A capacitor contains two metallic plates that do not touch each other and are separated by a material called a dielectric. The dielectric of the capacitor can be air or even vacuum but generally a non-conducting material or an insulator like glass, waxed paper, or different types of plastics. The dielectric provides the following advantages:-

1. The dielectric constant(k) is the property of the dielectric material and changes from one to another material which is used for increasing the capacitance by a factor of k.
2. The dielectric material is used to support the plates and allow the plates to be closer together without touching them.
3. The dielectric/insulator material can increase the maximum operating voltage as compared to air.
4. Dielectric permittivity can increase capacitance.

Thus an insulator is used in a capacitor.