We found this circuit in the July 1988 Radio Electronics magazine. The frequencies are given by capacitor C1 and the voltage input is made at pin 1.
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...