A touch activated toggle switch can easily be made by using a CD4017 IC with few other components. The CD4017 is a decade counter IC that is wired here as a toggle switch. The IC will toggle between the pin 2 and 3 on each positive pulse receive at the clock input pin 14.
The two different circuits
are shown here which can be used to activate any AC or DC device by touching the touch plates shown in the diagram.
The circuit shown in the figure 1 is using a PNP transistor; it provides a positive pulse at the clock input pin of the IC each time you touch the touch plate shown in the schematic. The touch plate is connected between transistor's base and ground or negative.
The figure 2 is using a darlington transistor. The darlington transistor have a high gain as compare to a normal transistor. Therefore we have used a darlington transistor to increase the sensitivity of the circuit to operate the IC by touching only base of the transistor.
The 2N4401 transistor is used to drive the relay. The operating voltage of the IC is 9 to 12V DC.