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Monday, September 28, 2009

Touch Switch Circuit Using 555 IC

This is a circuit for touch switch circuit. This circuit is almost same with touch door alarm. This circuit uses a 555 timer as the bases of the touch switch circuit. This is the figure of the circuit.

The operation of this circuit is begin, when the plate is touched the 555 timer is triggered and the output on pin 3 goes high turning on the LED and the buzzer for a certain period of time. The time that the LED and the buzzer is on is based on the values of the capacitor and resistor connected to pin 6 & 7. The 10 M resistor is on pin 2 causes the circuit to be very sensitive to the touch.


  1. how much output will produced.....................

  2. i hv build this ckt bt i facing a problem i.e when i connect the battrey the ckt LED glows without touching the sense plate and to reset the ckt i hv press 10M of resitor.. why so..???

    Pls reply..