Notch Filter Calculator

Center Frequency (Hz):
Capacitor Sequence:
Resistor Scale (Ohms):
Co (pF): Ro (Ohms):
Ro_low (Ohms): Ro_adj (Ohms):
Rq (Ohms):

The filter topology here is the Fliege topology. I have found this to be the most stable and most easily tuned notch filter topology.

Tuning is done by varying Ro _adj. If you do not want the adjustment capability, make Ro_low + Ro_adj = Ro.

The Q setting is preset to 10. This has little meaning for the depth of the notch, which is theoretically infinite. It is primarly a measure of how much you will disturb the frequencies around the center. Q's of 100 start eroding the notch depth, tuning becomes difficult, and the bandwidth of the op amp comes into play. So 10 is a really good value - stick with it unless you really know what you are doing.