INDIRECT TOUCH SWITCH FOR ELECTRIC APPLIANCE

摘要

PURPOSE: An indirect touch switch for electric appliance is provided to perform a switch function without exposing a shape of switch by using a variance of electrostatic capacitance. CONSTITUTION: An indirect touch switch is formed with a touch detection portion(10), an oscillator(20), a rectifier(30), a differential amplifier(40), and a comparator(50). The touch detection portion(10) changes electrostatic capacitance according to a touching state or an approaching state of a user's finger. An oscillating frequency of the oscillator(20) is changed according to the changed electrostatic capacitance. The rectifier(30) is used for converting a changed oscillating signal of the oscillator(20) to a direct voltage. The differential amplifier(40) is used for amplifying the direct voltage of the rectifier(30). The comparator(50) is used for comparing the amplified voltage of the differential amplifier(40) with a reference voltage and generating a switching signal.