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 bidirectional current sensing circuit was found in a 2005 Linear Technology application manual....
We found this circuit in the November 1992 Radio Electronics magazine. The circuit uses an LDR as a...
This circuit is intended to manipulate a transmitter (CW) from coded audio signals recorded on a...