Electrical Engineering ⇒ Topic : Capacitor

CAPACITOR

A capacitor consists of two parallel conducting surfaces shown in Figure (a) separated by a dielectric that acts as an insulating medium. The main purpose of capacitor is to store electrical energy by means of electrostatic stress in the dielectric. The conducting surfaces of a capacitor may be rectangular, circular or cylindrical. The common word condenser is a misnomer since a capacitor does not condense electricity.

                                                      figure (a)

Capacitor:-

Any two conducting surfaces separated by an insulating material is called a *capacitor or condenser. Its purpose is to store charge in a small space.

• The conducting surfaces are called the plates of the capacitor and the insulating material is called the **dielectric. The most commonly used dielectrics are air, mica, waxed paper, ceramics

   etc. The following points may be noted carefully

• The ability of a capacitor to store charge (i.e. its capacitance) depends upon the area of plates, distance between plates and the nature of insulating material (or dielectric).
• A capacitor is generally named after the dielectric used e.g. air capacitor, paper capacitor, mica capacitor etc.
• The capacitor may be in the form of parallel plates, concentric cylinder or other an-angement.