A button switch is simply called a button. It is usually used to switch on and off the control circuit. It is a low-voltage electrical appliance that issues a command in electric drag. Send out control signals to control contactors, relays, electromagnetic starters, etc. Its characteristic is that it is installed in the working machine and instrument. It is in the initial free position most of the time. Only when required, it is switched to the second state (position) under the action of external force. Once the external force is removed, Due to the action of the spring, the switch returns to the initial position.
Button switches can complete basic controls such as start, stop, forward and reverse, speed change and interlock. There are usually two pairs of contacts for each push button switch. 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 move simultaneously, the normally closed contact opens, and the normally open contact closes.