Electromagnetic relay is an important part of bell, telephone and automatic control circuit device, the essence of which is controlled by the electromagnet switch, in the circuit plays a role similar to the switch:
(1) With low voltage, low current control high voltage, high current;
(2) to achieve long-distance control and automatic control.
The use of electromagnetic relays can be low voltage, weak current control circuit to control high voltage, high current operating circuits, and remote control and production automation. Electromagnetic relay is widely used in automatic control (such as refrigerators, cars, elevators, machine tools In the control circuit) and communications.