Employing the XR2206 IC, this circuit was found in the May 1977 issue of Radio Electronics magazine. The formula next to the diagram gives the component values as a function of frequency.
This filter was found in the October 1969 issue of Radio Electronics magazine. The frequency...
The circuit in the figure has the same purpose as the previous one (CBV15991E), except that it has a...
Found in a Popular Electronics from the 90s, this circuit can be adapted to use LEDs. The power...