This audio amplifier circuit was found in Radio Electronics magazine from June 1966. The circuit is a commercial RCA type and is powered by mains power.
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...