This CMOS 4001 oscillator alternately turns the relay on and off at times set by R2. The circuit is from Electronics Now magazine, June 1995.
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...