This is a simple Electronic Time On Touch Switch Circuit Diagram. The circuit is built around a 555 oscillator (Ul), which is turned on when a trigger is applied by touching the touch terminal to pin 2 of Ul. When activated, LED1 and BZ1 (a piezoelectric buzzer) turn on for the time period set by the values of R2 and C.
The ON-time of the touch circuit can be altered by changing the values of Ci and R2. This touch switch can be powered from batteries so that it need not be near a 60-Hz power source for triggering. The extremely small amount of current supplied to the trigger input through the 10- resistor. Rl, makes the input circuitry very sensitive to any external loading, and it is easily triggered by touching the pickup.