Indicated for automotive use, this circuit was found in a Popular Electronics from the 90s. The circuit uses a power transistor that must be equipped with a heatsink.
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...