This complex circuit was found in the 1993 edition of the Electronics Experimenter's Handbook. Most of the components are still common today.
This circuit appears in many similar configurations on this site. This one is from the March 1984...
This circuit can be tuned in a 100 kHz band around the frequency of the crystal. The transistor can be...
This circuit with the HA2400 was found in the March 1980 Radio Electronics magazine. The circuit has...