The configuration shown was found in the October 1974 Radio Electronics magazine. The integrated circuit used is the CD4001 and the power supply depends on the application.
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...