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 two-tone decoder has a bandwidth of 24%. The circuit is from a 1994 Electronics Now. The...
Bike speedometer (CB20497E) This circuit can be powered by a solar cell. The circuit is from a...
This is a typical common collector amplifier step configuration. The transistor can be used...