Capacitive touch sensors are based on the electrical capacitance of the human body. When, for example, a finger comes close to the sensor, it creates a capacitance to Earth with a value of 30 to 100 ...

This is a very simple touch light switch circuit that uses the 4011 IC, one transistor and a relay. The C1 capacitor stores the switching state at a certain time and is charged or discharged according ...