A very simple touch switch circuit diagram can be constructed using this circuit schematic . This circuit will turn on /off an electronic relay using the same touch sensor . This touch switch circuit ...

For a reliable operation, select the relay’s operating voltage as 2/3 to 3/4 of the main power supply. For example is using a 12V power supply select a 9V relay. Transistors replacements: T1 = 2SA499 ...