This circuit was found in the February 1990 issue of Radio Electronics magazine. The gain is given by the capacitors according to the table next to the diagram.
This circuit was obtained in an Electronic Design from the 80's. It has the adjustment of the gain...
This circuit was obtained in a 1977 magazine, but it can still be easily assembled, as the...
This circuit uses only passive components and must be tuned to the operating range. The circuit is...