Micro Circuit Breaker, usually referred as MCB, a terminal protection appliance widely used in terminal building equipment. It is used as protection for single-phase, three-phase, overload, overvoltage under 125A, including four sizes, unipolar 1P, two-pole 2P, three poles 3P, four poles 4P.

It is also known as ship type switch. Its structure is the same with toggle switch, the difference is just the shape. Rocker switch is usually used as an electronic device's power switch, the contacts include SPST and DPDT, and some also with lights switch.

Low-voltage apparatus is a kind of component or equipment turning on or off the circuit either manually or automatically according to the requirements or signals from outside, thus achieving the object of switch, control, protection, detection, transformation and regulation of the electrical circuit.

In electrical engineering, contactors can be both cut off main circuit of AC and DC quickly, and connect frequently with equipment controlled with large current (up to 800 amps) unit of the circuit, so they are often applied to the motor as the control object.

According to the working environment temperature changes, physical deformation occurs inside the switch, resulting in some special effects to generate a series of actions like turning on or off.

Auto relay is made up of a magnetic system, contact system and restoration mechanism. Magnetic system includes the iron core, the yoke, the armature coil and other parts.