This circuit makes use of comparators and common operational amplifiers, having been found in Motorola Linear Interface ICs of 1993. The circuit requires symmetrical source.
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...