We found this circuit in a 1969 General Electric documentation. The circuit uses transistors of the time and the diodes in the dotted board must be mounted on the output transistor heatsinks.
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...