The circuit breaker is designed for automatic operation of electrical switches to protect the overload or short circuit that may cause damage to the circuit. Its basic function is to detect fault conditions and stop the current immediately by interrupting continuity. Unlike a fuse that has been used once and then needs to be replaced, the circuit breaker can be reset (manually or automatically) to resume normal operation. The circuit breakers are divided into different sizes. They can protect the switches of personal household appliances. The large ones are designed for high-voltage lines to protect the whole city.

The time control switch is a power switch control device. It can automatically turn on and off the power of various electrical equipment according to the time set by the user. In order to automatically turn on and off the power of various electrical equipment in the future. It is convenient for work and life. The travel time is accurate and the operation is simple.

Relay is an electrical control device. When the change of input quantity (excitation quantity) reaches the specified requirements, it is an electrical appliance that makes the controlled quantity change in a predetermined step in the electrical output circuit. 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 circuit, it is actually an "automatic switch" that uses small current to control large current operation. Therefore, it plays the role of automatic adjustment, safety protection and conversion circuit in the circuit.

SPD surge protective device is an electronic device that provides safety protection for various electronic equipment, instruments and communication lines. When the electrical circuit or communication line suddenly generates peak current or voltage due to external interference, the surge protector can conduct shunt in a very short time, so as to avoid the damage of surge to other equipment in the circuit. The surge protector is applicable to AC 50/60HZ, and the rated voltage is 220V to In the 380V power supply system, indirect lightning and direct lightning impact or other transient over-voltage surges are protected, which is applicable to the requirements for surge protection in household, tertiary industry and industrial fields.

Contactors are divided into AC contactors (voltage AC) and DC contactors (voltage DC), which are used for power, power distribution and electric field combination. In a broad sense, a contactor refers to an electrical appliance that uses the current flowing through the coil to generate a magnetic field to close the contact in order to control the load in industrial electricity.