proximity reed switch contains a pair (or more) of magnetizable, flexible, metal reeds whose end portions are separated by a small gap when the switch is open. The reeds are hermetically sealed in opposite ends of a tubular glass envelope.
proximity reed switch is an electrical switch operated by an applied magnetic field. It consists of a pair of contacts on ferromagnetic metal reeds in a hermetically sealed glass envelope. The contacts may be normally open, closing when a magnetic field is present, or normally closed and opening when a magnetic field is applied. The switch may be actuated by a coil, making a reed relay,or by bringing a magnet near to the switch. Once the magnet is pulled away from the switch, the reed switch will go back to its original position.
An example of a reed switch’s application is to detect the opening of a door, when used as a proximity switch for a burglar alarm.