Found in an Electronics World of 1966 this circuit can be made with current power transistors. It causes colored lamps to flash to the rhythm of the audio signal applied to the input.
Published in Popular Electronics with the curious name of Obnoxious Noisemaker, this 1968 circuit...
This preamplifier circuit for turntable cartridges was found in the March 1994 issue of...
E) This circuit was found in documentation from the 1980s. The integrated circuit used is not very...