This circuit is from a documentation from the 70s. The circuit uses logic gates of the time, which in many cases were arrays of transistors allowing use as audio amplifiers, as in this case.
This small-range MW transmitter can be used as a wireless microphone. The circuit is from an...
This single-transistor oscillator was found in Radio Electronics magazine from February 1962. The...
This source for common, non-high-power car radios can be used on the bench. It was found in a...