The circuit breaker can extinguish the arc and has the ability of subsection to protect the circuit. The contactor uses the coil to control the circuit to break, when the contactor is energized, the normally open is closed, and the long closed is closed, so that it can be controlled.

1. The miniature circuit breakers mainly for protection, but not overheating broke off, and its protection is currently more commonly used three sections of protection, both overload protection, short-circuit, short delay, long long delay. There are some undervoltage, overvoltage and other protection functions. Specific depending on the brand, model and fixed. The switch can be operated by hand or by electricity. There are three ways of installation: fixed type and drawer type. According to the magnitude of current and the level of operating voltage, low voltage molded case circuit breaker, low voltage frame breaker and high voltage vacuum circuit breaker can be divided into low voltage circuit breaker. According to the difference of trip curve, it can be divided into different occasions. And fuse is still very different.

2. Contactor is mainly used for industrial control. The main load is motor. Of course, some heaters will be used and double power switches will be used. The on-off of the contactor is achieved by controlling the coil voltage. According to the different structures of arc extinguishing, they can be divided into vacuum contactor and ordinary contactor. According to the different control voltage can be divided into DC contactor and AC contactor, its main accessory is auxiliary contact.