Magnetic switch means induction through magnets. This "magnet" is a magnet. There are several kinds of magnets. Commonly used magnets on the market include rubber magnets, permanent ferrite magnets, sintered NdFeB, etc. The switch is the reed switch. Reed switch is the abbreviation of dry reed switch. It is a passive electronic switching component with contacts. It has the advantages of simple structure, small size and easy control. Its outer shell is generally a sealed glass tube, and the tube contains There are two iron elastic reed electric plates filled with inert gas. Usually, the two reeds made of special materials in the glass tube are separated. When a magnetic substance is close to the glass tube, under the action of the magnetic field lines, the two reeds in the tube are magnetized and attracted to each other. The reeds will attract together, connecting the circuits connected to the nodes. After the external magnetic force disappears, the two reeds separate due to their own elasticity, and the circuit is disconnected. Therefore, as a line switching device controlled by magnetic field signals, the reed switch can be used as a sensor for counting, limiting, etc. (mainly used in the production of door magnets and window magnets in security systems), and at the same time It is widely used in various communication equipment. In practical applications, permanent magnets are usually used to control whether the two metal pieces are connected or not, so they are also called "magnetrons".