Twin T Notch Filter Calculator

Enter Desired Center Frequency (Hz): Enter Desired Q: Select Resistor Sequence: E96 E24 Select Capacitor Sequence: E24 E12 E6 Select Resistor Scale (Ohms): 1 10 100 1000 10000 100000 1000000     C1, C2 (pF) Ro (Ohms) Rq low (Ohms) Rq high (Ohms)

Enter the Center Frequency and click "Calculate" There will be a sharp peak somewhere near your selected center frequency - although component tolerance may put it off a bit.

I've also added two resistors that allow some control over the Q and gain. Don't vary the Q much from 10 - over a range of 0 to 30 you have some control, but it is not entirely linear or predictable.

The Twin T Notch topology is sensitive to the input impedance of the op amp. Use a JFET or other high input impedance op amp to make it work properly.