In this charger the current is limited by the incandescent lamp. Lamps from 40 to 100 W can be used and even connected in parallel, depending on the load.
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...