Found in 1980s Electronics Design, this circuit covers 4 decades of frequencies with a unique control. A multi-turn trimpot is used for fine adjustment. The frequency range depends on C1.
We found this circuit in a Radio Electronics. The circuit can be seen elsewhere on this site. The...
Found in old American documentation, this filter has a 8 dB per octave attenuation. The formulas for...
The circuit presented is from the Linear Applications Handbook of the National Semiconductor of...