APPARATUS FOR CONTROLLING TEMPERATURE OF ELECTRIC HEATER

摘要

PURPOSE: An apparatus for controlling temperature of an electric heater is provided to restrain generation of noise and electromagnetic waves by using a phase control method. CONSTITUTION: A current control portion(10) drops a voltage supplied to a heat coil through the first silicon control rectifier(SCR1) by using a resistor and detecting a value of the dripping voltage. A phase detection portion(20) detects a phase of the voltage provided from the current control portion(10). An amplifier portion(30) amplifies a detection signal of the phase detection portion(20). A comparator portion(40) compares the amplified voltage of the amplifier portion(30) with a reference voltage. A delay portion(50) delays an output signal of the comparator portion(40) during a predetermined time and controls the voltage provided to the heat coil through the second silicon control rectifier(SCR2).