Relay can be seen everywhere in daily life, the application is quite extensive; But in the process of daily use, the relay also faces many problems: the coil will be burned if the given current is too large, and the relay can not work stably if the current is too small. Contact switching voltage and current must also be kept within the normal range, otherwise it is easy to damage the contact of the relay. At the same time, with the gradual popularization of Internet of Things channels and 5G communication technology, people put forward higher and more stable requirements for signal transmission and reception, and the original relay obviously cannot meet people's needs. In such a user's overall use of the environment, the Yuan is the electromagnetic relay out, strong attack. 1. Synthesis signal: for example, when multiple control signals are input into the multi-winding relay in the prescribed form, the predetermined control effect is achieved after comparison and synthesis. 2. Amplification: for example, sensitive relays, small relays, intermediate relays, etc., with a very small amount of control, can control a large power circuit. 3. Expand the control range: for example, when the multi-contact relay control signal reaches a certain value, it can change, open and open the multi-channel circuit at the same time according to the different forms of the contact group. 4. Automatic, remote control, monitoring: for example, the relay on the automatic device, together with other electrical appliances, can form a program control line, so as to realize automatic operation. Electromagnetic relay is widely used in automatic control (such as refrigerator, car, elevator, machine tool in the control circuit) and communication field, to meet the higher frequency requirements of these devices to relay, can play their greater performance.