One Touch to ON-OFF Switch

Timer IC555 gives timing output pulse depends on triggering input applied at the terminal 2 (trigger input) and the duration of pulse depends on timing resistor and capacitor connected between terminal 7 and terminal 6.

Here we can convert IC555 into On / Off touch switch by removing timing capacitor this will avoid pulse duration limits at output.


Make touch metal piece for on / off control, and then place with trigger (pin2) input and Threshold (pin6). Placing Ground supply plate near to trigger pin makes On switch and placing Positive supply plate near to threshold pin makes Off switch.

The output terminal (pin3) connected with LED, here you can connect relay switch to control any device.


Components List

S.No Name Quantity
1. IC 555 1
2. LED 1
3. Resistor 1MΩ
Resistor 330Ω
4. Capacitor 0.01uF 1
5. Small metal piece
(for touch switch)

2 thoughts on “One Touch to ON-OFF Switch

  1. When would some one use this ? GIve some examples please. I am new to Electronics but interested in some small circuits like this.
    So,If I can get some practical examples or test cases – this would help understand the concept better.

    1. It is used in many lamps and wall switches that have a metal exterior as well as on public computer terminals. A touchscreen includes an array of touch switches on a display. A touch switch is the simplest kind of tactile sensor.

      Yeah its late reply but Every Questions to be Answered. 🙂

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