What is a relay? From the definition of a relay, a relay is an automatic control device that will change the output by jumping when the input (electricity, magnetism, sound, light, heat) reaches a certain value. The relay is actually an electronic control device. It has a strong control system (also known as an input loop) and a controlled system (also known as an output loop). It is usually used in automatic control circuits. It actually uses a smaller current to A type of "automatic switch" that controls larger currents. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

The four functions of the relay are as follows:
1. Expand the scope of control.
When the control signal of the multi-contact relay reaches a certain value, it can open, switch, and connect multiple circuits at the same time according to the different forms of the contact group.
2. Zoom in.
Sensitive relays, intermediate relays, etc., can control high-power circuits with a very small amount of control.
3. Synthesized signal.
When multiple control signals are input to the multi-winding relay in a specified form, the predetermined control effect is achieved through comparison and synthesis.
4. Automatic, remote control and monitoring.
The relays on the automatic device, together with other electrical appliances, can form a program control circuit to realize automatic operation.