A touch switch is a switch that is turned on and off by touching a wire contact, instead of flicking a lever like a regular switch. Touch switches have no mechanical parts to wear out, so they last a lot longer than regular switches. Touch switches can be used in places where regular switches would not last, such as wet or very dusty areas.

 

Schematic

Parts

Part	Total Qty.	Description	Substitutions
C1	1	10uF 16V Electrolytic Capacitor
R1, R2	2	100K 1/4 Watt Resistor
R3	1	10 Meg 1/4 Watt Resistor
U1	1	4011 CMOS NAND Gate IC
MISC	1	Board, Wire, Socket For U1

Notes:

1. The contacts an be made with just two loops of wire close together, or two squares etched close together on a PC board.

2. When activated, the output of the circuit goes high for about one second. This pulse can be used to drive a relay, transistor, other logic, etc.

3. You can vary the length of the output pulse by using a smaller or larger capacitor for C1.