Despite being found in a 1980 publication, this circuit uses components that can still be found easily. The circuit feeds an array of LEDs that run randomly, stopping at one.
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...