Electromagnetic Relay

A relay is an electrical switch that uses an electromagnet to move the switch from the OFF to ON position.  It takes a relatively small amount of power to turn on. Both AC and DC relays are used in industrial applications. Contact between the Common terminal and NC terminal will keep relay if power is applied to the coil. common terminal make contact with NO when energies the coil. SPDT and DPDT relays are commonly used in industries.