Found in an American documentation from 1969, this circuit makes use of a pair of matched transistors of the time. The circuit supports modern equivalent components.
This circuit was found in a 1980s documentation. The diodes may be general purpose diodes such as 1N34...
In the figure below we have the typical circuit of an automotive star alternator with the...
This circuit with germanium transistors was found in documentation from the 50's. The transistors are...