The indicator for this circuit is a 0 to 1 mA milliammeter. The operational is from the 70s, when the circuit was published. Modern equivalent can be used.
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...