A Thermal Reed Switch is an assembly consisting of a Reed Switch, a Thermal Ferrite and two permanent magnets and this assembly works as a temperature sensor.
At temperatures lower than the Thermal Ferrite’s Curie Point, the magnetic flux lines between the two exterior magnets are connected and enlarged as a whole and this keeps the reed switch contact closed. When the ambient temperature crosses the Thermal Ferrite’s Curie Point, the flux no longer passes between the exterior magnets, and the reed switch contact opens.
