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.
The signal from this circuit found in a 1968 Electronics World is sinusoidal and depends on the...
This circuit uses a sensitive vibrator that can be made with a reed-switch to activate a relay from...
This amplifier can be powered with voltages between 2 and 5 V with power up to 100 mW. The minimum...