1. Expand the control range: for example, when the control signal of the multi-contact relay reaches a certain value, the multi-circuit can be switched on, disconnected and connected at the same time according to different forms of the contact group.
2, amplification: for example, sensitive relays, intermediate relays, with a very small amount of control, can control a large power circuit.
3. Comprehensive signal: for example, when multiple control signals are input into the multi-winding relay in the prescribed form, the predetermined control effect can be achieved after comparison and integration.
4, automatic, remote control, monitoring: for example, the relay on the automatic device and other electrical appliances together, can form a program control line, so as to achieve automatic operation.
Relay (English name: Relay) is an electrical control device, which makes the controlled quantity in the electrical output circuit predetermined step change when the change of input quantity (excitation quantity) meets the specified requirements. It has the interaction between the control system (also called the input loop) and the controlled system (also called the output loop). Usually used in automatic control circuits, it is actually a small current to control the high current operation of an "automatic switch". Therefore, it plays the role of automatic adjustment, safety protection and conversion circuit in the circuit.