Found in a 1980s telecommunications documentation, the circuit presented acts as a product detector. The modulator or mixer in the square may be that of the previous circuit.
With a strong positive feedback (via a 10 M resistor) we can get the trigger setting for the...
The critical component of this circuit is the transformar. We found it in an 1980s documentation....
This old oscillator using germanium transistors has a high impedance headphone as inductor to...