System principle of magnetic door switch

Door sensor system is a kind of safety alarm system, divided into door sensor and window sensor (the same principle, different shapes). The door/window sensor is not easy to see if you are not paying attention. The so-called door sensor/window sensor is actually the abbreviation of door sensor switch and window sensor switch. It consists of two parts: the smaller part is a permanent magnet, and there is a permanent magnet inside to generate a constant magnetic field, and the larger one is the door. The magnetic body, there is a normally open type reed switch inside. When the permanent magnet and the reed switch are close (less than 5 mm), the door sensor is in the standby state, when the permanent magnet is a certain distance away from the reed switch After that, it is in the normally open state. Magnets and reed switches are installed in the door frame (window frame) and door leaf (window sash) respectively. They are basically embedded (also surface-mounted), so people in the industry generally don't notice these. You can open the household door and exterior window, and look at the top of the household door frame and the window frame of the exterior window. You can see the round, generally white components. In fact, this is the so-called door magnet and window magnet.