We found this circuit in an old American publication from the 1980s. Transistors can be general-purpose types like the BC548, and the tuning frequency is given by the L and C components.
This circuit is from a National Semiconductor manual from the 90s, using an integrated regulator for...
The purpose of this amplifier that we found in the Radio Electronics magazine of October 1952 is...
This configuration, which appears on other circuits on this site, was found in a European...