Electronic top hat rail thermostat, top hat rail temperature controller THERMASREG® TET for installation in distributor boxes or control cabinets, with switching output and multi-range switching and adjustable hysteresis. Suitable for electronic control and monitoring of temperatures by remote sensors, in the residential sector (e.g. in underfloor heating systems), in halls, greenhouses and in the industrial sector. The controller is equipped with sensor breakage detection and a switch-off function.