TEMPERATURE CONTROL CIRCUIT EMPLOYING A VARIABLE RESISTANCE HEATING ELEMENT

摘要

The present circuit employs a heating element whose electrical resistance varies in response to the heat generated thereby. The heating element comprises one leg of a bridge circuit and the output signal from the bridge circuit is connected to fire a silicon-controlled rectifier. The silicon-controlled rectifier is connected to short out a leg of the bridge circuit which is serially connected to the heating element thereby providing full power for energizing the heating element when the silicon-controlled rectifier is turned on and simply providing control current to the heating element when the silicon-controlled rectifier is turned off.