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 symmetric 30 mA x 15 V power supply was found in the Ferranti transistor manual from 1974....
We found this circuit in a technical documentation on thyristors from the 70s. The circuit is set...
August 2017 - Microchip's new ATtiny1617 8-bit AVR microcontrollers running at 20 MHz and 16 kB...