This circuit can be used as an amplifier for musical instruments or even with your cell phone. The circuit is old and was found in the 1990 edition of Radio Electronics Experimenter magazine.
This bench circuit with no active components appeared in the August 1958 Radio Electronics...
The operational amplifier of this balanced circuit is old and can, however, be implemented with...
This circuit generates 5 notes in sequence, which are programmed in the connections of the 4017...