This converter for WWV time reference station signals was found at Popular Electronics. The 15 MHz signals are now received on a medium wave radio at 1 MHz.
This timer, from an old American publication, uses indicator lamps, but can be modified to use...
This didactic circuit from a 1977 Radio Shack documentation shows how to use the 741 as a...
Found in an 80's Hands On Electronics, this circuit turns on a light when it gets dark and goes...