This circuit is from 1999 documentation. The integrated circuit used is not very common today. Both transistors are used if the motor current is greater than 500 mA.
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...