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 600-ohm output impedance circuit was found in a Radio Electronics from October 1963. The...
Used with infrared remotes at the time, this circuit was found in a 1991 RE Experimenter Handbook....
The circuit presented was obtained in a technical documentation from National Instruments. The...