Using the 4001 integrated circuit, this latching relay can employ any general-purpose transistor. The power supply is according to the relay with voltage up to 12 V.
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...