If you have the skills and can get your hands on SMD components, you can assemble this small amplifier. We found it in the Radio Electronics Experimenter special edition from 1990.
The circuit suggested in the figure differentiates the signal from the negative front of a...
This frequency triple oscillator circuit was found in an American publication in 1967. The FET is...
This circuit was originally recommended for an electric oven warning system. However, we can use...