This circuit was found in a 1965 General Electric documentation. It is intended for reception of the aviation strip, but inside an aircraft or nearby (which is now prohibited).
This circuit allows the activation of a remote telephone bell made with a common piezoelectric capsule. The...
This circuit for analog VHF televisions was found in the 1989 Radio Electronics Experimenter...
The assembly of this circuit with 3 transistors was described in an article in Radio Electronics magazine...