SPTM-70 thermal fire detector

Principle of operation: a ferromagnet with metal plates is put on the reed switch, when the ambient temperature rises, the plates heat up, the ferromagnet heats up. When heated, its magnetic properties are gradually lost. At a certain temperature, a complete loss of magnetic properties is obtained, the contacts of the reed switch open.

Specifications:
The response temperature is 70°C.
The resistance of the sensor in standby mode is no more than 0.5 Ohm.
The resistance of the sensor in the "Fire" mode is at least 200 kOhm.