We found this circuit in the 1977 RCA Solid State ICs. The circuit consists of a current amplifier with a gain of 1000. The supply must be made from a symmetrical source.
This circuit is from 1987 documentation. The original project was carried out with the tape...
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
This VCA was found in the July 1988 issue of Radio Electronics magazine. It uses an OTA op amp and...