100 Seconds Duration On Switch with Touch Control by LM555 Schematic Diagrams Comments Off on 100 Seconds Duration On Switch with Touch Control by LM555 ]]>
This is a touch controled switch which keeps the circuit on about 100 seconds after touching the plate connected to the 2 numbered pin. At the end of this time duration, relay releases and the circuit gets to off position.
The impedance of the trigger input of the 555 timer IC is very high and the inductive voltage on the human body is enough to trigger it. The circuit works based on this principle. You can use a piece of metal as a plate. The circuit can be used in toy circuits, buzzers or any project that is suitable. You can adjust the duration time by changing the R1 and C1 values.