This variable filter circuit was found in July 1975 Radio Electronics magazine. The circuit uses 3 general purpose op-amps like the 741 and must use a symmetrical source.
July 2017 - The Texas Instruments TAS5782M Closed Feedback- Class D Amplfier Evaluation Module can now...
This circuit can be controlled by pin 1 through the output of a microcontroller functioning as a...
Found in a documentation for radio amateurs from the 90s, this circuit is suitable for RF...