This control circuit up to 1 kW was found in a 1967 RCA documentation. The components are from that time, and modern equivalents can be used.
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...