This transistor gain test was published in Radio Electronics magazine in July 1959. The transformer used is a special type common at the time. The circuit tests general-purpose transistors.
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...