Key switch, also known as touch switch, is an electronic switch. When in use, the switch can be turned on by gently pressing the switch button. When the hand is released, the switch is turned off. Its internal structure is realized by the bouncing of metal spring. Microswitch is widely used in household appliances because of its small size and light weight, such as color TV buttons, DVD player buttons, computer mouse and so on. However, the microswitch also has its shortcomings. Frequent pressing will make the metal shrapnel lose elasticity and fail. Therefore, the buttons of most electrical appliances are replaced by conductive rubber, such as computer keyboard, remote control, etc.

It can also be used to control low-power household appliances such as lighting lamps and exhaust fans. The electronic switch will be automatically disconnected after the mains power is cut off and will not be automatically connected when it is called again (it can be connected only by pressing the control button), which can avoid the consumption of electric energy or accidents caused by the long-term power on of electrical appliances.