Door Window NC Contact Security Alarm Magnetic Sensor Reed Switch Sets

Switch Type: NC(normal closed type), the circuit is closed normally, and, that if a magnet not near it, the circuit open.
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.

• Package Content: 1 x Magnetic Door Switch Sets, Installation Screws; Type: /; Rated Voltage: DC 100V
• Rated Current: 500mA; Rated Power: /; Wire Length: /
• Main Color: White; Contact Type: NC(normal closed type); Operating Distance: 17mm-25mm
• Big One Size(Approx): 64 x 20 x 13mm / 2.5" x 0.8" x 0.51"(L*W*H); Small One Size(Approx): 64 x 13 x 13mm / 2.5" x 0.5" x 0.51" (L*W*H)