The circuit shown is from National Semiconductor's Linear Applications Handbook. It makes use of the LM78S40 which is not an easy component to obtain today.
This reflex receiver for the mid-wave range employs germanium transistors of the time. We found it in...
Using a 106 series SCR, this circuit was found in the May 1971 Radio Electronics magazine. The...
This circuit was found in an old manual of linear integrated circuits of the 80's. Equivalent...