Switching control: The most common role of relays is as switching control devices. When the input signal meets the predetermined conditions, the relay can switch or control the on-off state of the circuit. Through relays, it is possible to achieve remote control of various electrical equipment, such as turning on/off motors, lights, heaters, etc.

Signal amplification: The relay can convert the input signal of low level or weak current into a high level or high current output signal, which plays the role of signal amplification. This function allows relays to be connected and controlled between devices with different voltages or currents.

Protection function: The relay can also provide circuit protection function. For example, an overload relay monitors the current in a circuit and cuts the circuit to prevent electrical damage when it exceeds a rating. Short-circuit relays can respond quickly and cut the circuit to prevent fire and other dangerous situations.

Logic control: Relays can control the operation of electrical equipment according to specific logic conditions. By installing multiple relays and using logic control and time delay devices, complex electrical control logic such as sequence control, cycle control and time control can be realized.

The multiple roles of relays make them an integral part of industrial automation and control systems. Through flexible configuration and application, relays can meet a wide variety of control needs and provide efficient and reliable electrical control solutions.