THE SAFETY DEVICE FOR TEMPERATURE CONTROL CIRCUIT

摘要

A temperature control apparatus has a first comparator circuit (COMPl) for comparing the voltage corresponding to thermal data provided by a thermal sensor (TH) with a first reference voltage generated in synchronism with the zero crossings of an AC power source (PS). The first comparator circuit generates a pulsative output voltage which is synchronous with the zero crossings of the AC power source. This output voltage causes a second reference voltage to be applied to a second comparator circuit in the form of a pulsative voltage.