Touch switch circuit composed of the photoelectric coupler

Published:2011/6/8 4:05:00 Author:Christina | Keyword: Touch switch, photoelectric coupler | From:SeekIC

Working principle: The circuit which is composed of the capacitance C5, the regulator tube VDW, the diode VD2, the capacitance C4 and the resistance R6 can supply the 12V DC working voltage for the control part. When the hand touches the sheetmetal S, the neon tube N is ignited, the N and the photoconductive resistance RG form the photoelectric coupler, so at this time the resistance of RG becomes small, this makes the pin-2's electric potential of the integrated circuit 555 is lower than 1/3 of the power supply voltage, because of the NE555 was taken up into the monostable trigger, so the pin-3 of 555 sends out a positive pulse to the counting trigger port 14-pin of the integrated circuit, there is one count of the CD4017.



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