A reed switch is a sensor that closes circuit in the presence of a magnetic field. Reed sensors can be used in many application where contact less On/Off is required. However reed switches can be fragile to use directly, hence this module can make it easier to handle and mount the sensor in various applications.
It is a kind of passive electronic switching component with contacts with a simple structure, small size and easy to control. It consists of a sealed glass envelope where there are two ferrous elastic reeds and is filled with inert gas called rhodium.