Push button switch is short for button, usually used to switch on and off the control circuit, it is an electric drive in a low voltage electrical instructions, widely used in a master electrical, in the electrical automatic control circuit, used to manually send control signals to control contactor, relay, electromagnetic starter, etc. Its characteristics are installed in the work of the machine, the instrument, most of the time is in the initial free state of the position, only when there is a requirement to switch to the second state (position) under the action of the external force, when the external force is removed, due to the action of the spring, the switch will return to the initial position.
Push-button switch can complete the start, stop, positive and negative rotation, speed change and interlock and other basic control. Usually each pushbutton switch has two pairs of contacts. Each pair of contacts consists of a normally open contact and a normally closed contact. When the button is pressed, the two pairs of contacts act at the same time, the normally closed contact is disconnected, the normally open contact is closed.
