NC means Normally Closed:When the magnet together, the circuit is conductive( light on ); when the magnet separate, the circuit is not conductive ( light off ). When make order,pls check carefully!The Reed Switch is an electrical switch operated by an applied magnetic field. It was invented at Bell Telephone Laboratories in 1936 by W. B. Ellwood. It consists of a pair of contacts on ferrous metal reeds in a hermetically sealed glass envelope. There are two types of reed switches: normally open reed switches and normally closed reed switches. The metal reeds on a normally open switch stay open when there is no magnet near the switch. In the presence of a magnetic field, the contacts of a normally-open reed switch will close. A normally-closed reed switch is closed when it is not near a magnet; as a magnet is brought close to it, a normally-closed switch will open.
