Electromagnetic current relay is an important component in electric bells, telephones and automatic control circuit devices. Its essence is a switch controlled by an electromagnet, which acts like a switch in the circuit:
(1) Use low voltage and weak current to control high voltage and strong current;
(2) Realize remote control and automatic control.
The electromagnetic current relay can be used to control the working circuit of high voltage and strong current with the control circuit of low voltage and weak current, and can realize remote control and production automation. Electromagnetic current relays are widely used in automatic control (such as control circuits in refrigerators, automobiles, elevators, and machine tools) and communication fields.