This audio oscillator is from a 1957 Raytheon publication. The tone generated depends on C2 and C2 and the handset must be high-impedance magnetic. Equivalent transistors can be tested.
The frequency of this oscillator depends on the crystal used and the transistors. The circuit was...
This circuit can be used to detect the signals from the previous circuit or from any radio...
We found this circuit in the Motorola Linear Databook of 1993. It is the traditional configuration with...