This circuit was obtained from an American technical manual from the 80's. The integrated circuit is an operational of the time that can be replaced by a modern equivalent.
This circuit is from Radio Electronics magazine from June 1958. The tuned range at the time was...
Found in Popular Electronics from the 90's, this tuned to infrared modulated receiver uses a PLL....
This circuit was found in the March 1979 issue of Radio Electronics magazine. Integrated circuits must...