This circuit was found in an American documentation from 1969. Indications of the used transistors are not given, but general-purpose types can be tested.
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...
We found this circuit in a Radio Electronics from January 1967. The SCR is already the C106, which...
This power source with silicon diodes at a time when valves were still used was found in Radio...