A magnetic switch, also known as a reed switch, is an electrical switch that is controlled by the presence or absence of a magnetic field. Its basic structure includes a hermetically sealed glass tube containing two ferromagnetic reeds, and the tube is filled with an inert gas to prevent oxidation. When a magnetic field is applied to the switch, the two reeds are attracted to each other and conduct; when the magnetic field is removed, the reeds return to their original position due to their own elasticity, thus disconnecting the circuit.

Magnetic switches are widely applied in various fields due to their simple structure, small size, low power consumption and high reliability. In the automotive industry, they are used for door status detection, trunk opening and closing sensing, and seat position sensing. In home automation, they are installed on windows and doors to form anti-theft alarm systems, which trigger alarms when the door or window is opened abnormally. In industrial production, they are used to detect the position of mechanical parts, such as the stroke control of cylinders and the positioning of conveyors.

Compared with mechanical switches, magnetic switches have no mechanical wear during operation, so they have a longer service life. They also have good resistance to vibration, shock and corrosion, making them suitable for harsh working environments. With the advancement of technology, magnetic switches have been developed into various types, such as normally open, normally closed and latching types, to meet different control requirements. They are an important component in the field of automatic control and sensing.