LE Sircut Magnet Door Contact, 5pcs Recessed Wired Security Door contact Sensor Alarm Magnetic Reed Switch, Magnetic Door Sensor, Connect Circuit, Magnet Away - Break Circuit (LEMS-108-5)

• Surface Mount Strong Magnet
• Stable Magnetic feild
• Suitable almost all Burglar Alarm system
• Suit for windows and doors
• Speical Strong Magnetic field
• 13 x 26 x 15mm Big Size Strong Magnet
• Voltage rating: 100VDC
• Current rating: 0.25A

These are used to secure an alarm circuit on a door or window. Sold as a pair, one has a magnet inside, the other a reed switch. They have powerful magnets, with self adhesive or screw mount, and screw terminal connections. Reed Switch contacts: closed when both units are together (ie current flows), and open when apart. Normally CLOSED (NC) per pair. Contact operation: Contacts are closed cicuit when the magnet is alongside the switch. For alarm installation this is denoted as the "normal" state as the door/window is secure and the alarm is armed. Contact operation: Contacts are closed cicuit when the magnet is alongside the switch. For alarm installation this is denoted as the "normal" state as the door/window is secure and the alarm is armed.