What is Relay and how it work ?

What is a Relay?

A Relay is an electromechanical switch and a protective device. A relay uses an electrical signal to control an electromagnet, which in turn on or off another circuit.
In a relay we give supply (220Vac or 24Vdc) to the coil side and then electromagnetic current flows through the coil and the switch becomes NC to NO.

Every electromechanical relay consists.

1. Electromagnet
2. Mechanically movable contact
3. Switching points and
4. Spring

How it Work.