This switch is triggered by the touch of the sensors, which can be two metal plates. These plates must be touched simultaneously to trigger the relay K1 to. The time during which the relay is activated is determined by the electrolytic capacitor and set to P1. The circuit sensitivity is set to P2. The relay used is 6V, because the power is 6V, but the circuit also operates at 12V by simply using an equivalent 12 volt relay. For longer drive times, increase the value of the electrolytic capacitor. For a single touch switch, ground the sensor terminal connected to the source negative. In this case, simply touch the other terminal to activate the circuit. Remember that the sensor connection wire cannot be too long, so that erratic triggering by capturing spurious currents does not occur. The transistor can be any general purpose NPN, just like the diode. The maximum load, which can be controlled by the relay contacts, is 2 amps per pair of contacts.
