The HD74HC245P is a CMOS LSI chip designed for use in automatic PIR lamp control. It can oper-ate with a 2-wire configuration for triac applications or with a 3-wire configuration for relay applications. The chip is equipped with opera-tional amplifiers, a comparator, timer, a zero crossing detector, control circuit, a voltage regu-lator, a system oscillator, and an output timing oscillator. Its PIR sensor detects infrared power vari-ations induced by the motion of a human body and transforms it to a voltage variation. If the PIR output voltage variation conforms to the criteria (refer to the functional description),