This is one of many possible touch switch configurations using CMOS integrated circuits. The circuit is from a 1980s American documentation. The power source must be isolated.
This circuit using a SIDAC is suggested by ON Semiconductor in its thyristor manual. The circuit...
September 2017 - Würth Elektronik High Power Ultraviolet LEDs can be obtained from Mouser...
The configuration shown was found in an old American manual. The circuit can be made with modern...