LEAKAGE CURRENT THERMOSTAT

摘要

LEAKAGE CURRENT THERMOSTAT The leakage current thermostat is utilized in an electric heater assembly including a housing, a heating element mounted in the housing, electrical supply lines to the heating element and an electrically insulating material in contact with at least a portion of the heating element. The material has a temperature-resistance relationship such that the leakage current therethrough is a steep function of temperature whereby changes in the temperature of the heating element. The leakage current thermostat includes a thermostat control circuit which is coupled to the supply lines and which is operative to control the current to the heating element in response to changes in the leakage current. The heating element is preferably formed by printed circuit techniques on a ceramic material which is affixed in a layer to a metal (conductive) base layer and the leakage current from the printed circuit element to the base is measured by the control circuit.