100 Seconds Duration On Switch with Touch Control by 555

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This is a touch control 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.

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Thank you.

This entry was posted on Thursday, February 7th, 2008 at 10:21 am and is filed under 555, Electronic Control. You can follow any responses to this entry through the RSS 2.0 feed.