We found this circuit in a Radio Electronics from December 1963. The circuit combines valves and transistors and has a high input resistance. The circuit is powered by two batteries.
This oscillator from an old publication uses one of the first commercial transistors, the CK722....
The integrated circuit used in this configuration is not common today. The zener determines the...
With good filtration, a battery charger can be used as a power source. The filter shock can be the...