Any high-gain Darlington transistor can be used on this touch circuit. The load can be formed by LEDs and the power supply isolated from the power grid.
This circuit is a from publication 1980, but still can be mounted with BC548 transistors for Q1...
This circuit for testing zener diodes by lifting their curve on an oscilloscope was presented in...
This high quality circuit with complementary symmetry was found in an Electronics World of 1966....