Found in American documentation from 1969, this circuit operates in the frequency range 10 to 150 Hz providing signals as shown in the diagram itself.
This interesting sensor for RF signals was found in an article in the June 1989 Radio Electronics...
The frequency of this oscillator depends on the inductor and capacitors in parallel with it. In...
This circuit was found in RCA and General Electric documentation from the 1980s. The circuit has...