Touch Switch II
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.