Essential components of an Electromagnetic Relay:
Electromagnetic Coil: A iron rod covered by copper turn which becomes a magnet when we supply DC voltage to it.
Control Spring: It is used to control the spring when an electromagnetic coil attracts the contact point. It gains its original shape when an electromagnetic coil is demagnetized. A spring controls the movement of the rod.
Contact Point: When an electromagnetic coil is magnetized contact point closed. It provides a continuous path to the alternating current.