This circuit from General Electric was found in a 1967 documentation. The SCR is of the time, as are the transistors, but equivalents can be used.
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...
Suggested by National Semiconductor, this circuit can be applied to almost any operational...
This circuit was found in Radio Electronics from the 90s. The circuit can generate signals up to...