A capacitor is composed of two conductors separated by an insulating material called a DIELECTRIC. The dielectric can be paper, plastic film, ceramic, air or a vacuum. The plates can be aluminium discs, aluminium foil or a thin film of metal applied to opposite sides of a solid dielectric. The CONDUCTOR - DIELECTRIC - CONDUCTOR sandwich can be rolled into a cylinder or left flat.

 In a way, a capacitor is a little like a battery. Although they work in completely different ways, capacitors and batteries both store electrical energy.

  HOW A CAPACITOR WORKS

When the circuit is switched on, the LED emits light and the capacitor charges up. When the switch is turned off the LED stills emits a light for a few seconds because the electricity stored in the capacitor is slowly discharged. When it has fully discharged it's electricity the LED no longer emits light. If a resistor is introduced to the circuit the capacitor charges up more slowly but also discharges more slowly. What will happen to the light ?

 

 Ceramic Capacitor

-is a fixed value capacitor in which ceramic material acts as the dielectric.

Electrolytic capacitor is a type of capacitor that uses an electrolyte to achieve a larger capacitance than other capacitor types.

 Epoxy Capacitor

                                               Typically the coupling capacitors are connected at the line terminal of motors and generators and in switch gear.