Switch :
A switch is used in an electric circuit as a device for making or breaking the electric circuit in a convenient way i.e. by the simple motion of a knob or handle to connect together or disconnect two materials to which wires or cables are connected
The switches may be classified into
(i)Air switches
(ii)Oil switches.
As the name implies Air switches are those whose contacts are opened in air, while oil switches are those whose contacts are opened under oil. Oil switches are usually employed in very high voltage high current circuits.
