Uses of Capacitors

Introduction to uses of capacitors:

Every conducting material has a capacity to hold charge. The shape, size and surroundings of the conductor have an influence on the amount of charge a particular conductor can hold. The quantity of charge that a conductor holds is linearly proportional to the potential difference between ends of a conductor. The capacity of material to hold charge is termed as conductance.

For any conductor, when the charge on the conductor is increased, its potential also increases. The charge on the conductor is directly proportional to the potential difference applied to the conductor.

Q a V

Q = CV

Here C is proportionality constant called as capacitance. So capacitance is

C = Q / V

Capacitance: It is the ratio of the magnitude of the charge on conductor to the magnitude of the potential difference between the ends of the conductor.

Unit of capacitance is coulomb / volt or farad.

Uses of Capacitors:

Storing Energy: In a small volume, capacitors can create a strong electric field. They are used to store large amount of energy. The best example is the Camera flash circuits that make uses of capacitor to store large amount of  energy and discharge when needed.

Uniform Strong Electric Field:  in some basic electrical appliances, there is a need of  electric field to interact with magnetic field. In such situation capacitors are used to create large electric field in a small volume.  The best example is electric motors and ceiling fans which require electric field to do mechanical work. Thus capacitors give the necessary torque to  start and also keep the motor rotate continuously.

Filters: Capacitor blocks direct current and allows alternating current. So they are used as filters in the circuit.

More Uses of Capacitors:

Tuning circuits: Tuning circuits are used in communication system to catch and transmit  electromagnetic waves. of certain frequency. For a tuning circuit, capacitors along with inductor  is connected in series are used.  A tuning circuit allows catching a particular radio frequency. Radio, TV receivers uses this principle.

Oscillating circuit and Amplifier circuit: Capacitors are used in production of AC signal or in timer circuits. The oscillating circuits has a capacitor connected either with resistor or inductor. capacitors are used as components in  all types of amplifier circuit to increase the given input signal.

Power supplies: Capacitors are used to reduce voltage fluctuations in electric power supplies as filters, to transmit regulated pulsed signal and to provide necessary time delay.