A Reed Switch Sensor Module is a magnetic field detection sensor built around a glass reed switch capsule and an LM393 voltage comparator IC. When a magnetic field (such as a neodymium magnet) comes near the green glass bulb, the internal ferrous contacts snap together, closing the circuit. The onboard comparator converts this contact state into a clean digital signal output (DO). It features a blue potentiometer for sensitivity adjustments and dual LED indicators for power and switching status.

This product is featured by Famephase Electronic Accessories as a reliable component for door/window security alarms, magnetic proximity sensing, speed counting, and limit detection.