| R1 |
1 |
10 Meg 1/4W Resistor |
|
| R2 |
1 |
47K 1/4W Resistor |
|
| R3 |
1 |
120k 1/4W Resistor |
|
| R4 |
1 |
470 Ohm 1/4W Resistor |
|
| C1 |
1 |
15uF Electrolytic Capacitor |
|
| D1 |
1 |
1N4007 Silicon Rectifier Diode |
|
| Q1 |
1 |
2N5458 N Channel Field Effect Transistor |
|
| Q2 |
1 |
2N2222 NPN Transistor |
2N3904 |
| Q3 |
1 |
2N3906 PNP Transistor |
|
| K1 |
1 |
Relay w/12V Coil, Contacts To Suit Application |
|
| MISC |
1 |
Board, Wire, Small Metal Pad For Touch Pad |
Similar to the CMOS based Touch Switch also on this
site, this transistor based touch switch can activate a load simply by the user
touching a metal plate. It is designed to directly switch a relay to allow it to
be used with large loads. As it uses only a few commonly available transistors
and a 12V supply, it is ideal for hostile environments where mechanical switches
would be damaged. Using a latching relay and two of these circuits, a simple two
pad "touch on/touch off" arrangement can be made.
|
