TEMPERATURE CONTROLLER FOR ELECTRIC HEATER

摘要

PURPOSE:To vary the temperature of a heating element in response to a room temperature and to always secure a pleasant level of temperature, by generating the temperature setting voltage with serial connection of plural diodes and resistances and varying said temperature setting voltage according to the change of the forward voltage of the diode produced by the change of the room temperature as well as the number of conductive diodes. CONSTITUTION:The temperature setting voltage VS is minimum at the position 1 of a changeover switch 41 and diodes 36-40 all conduct at the position 1 of the switch 41. Then the diodes 37-40 conduct at the position 2 of the switch 41. In such a way, the number of conductive diodes are successively reduced. Then the forward voltage is increased with diodes 36-40 as the room temperature is reduced. While the voltage VS is reduced with the temperature of a heating element 2 is increased. Thus the temperature of the element 2 is varied in response to the room temperature. Therefore it is no required for an operator to increase the setting level of temperature in response to the drop of the room temperature.