Notch Filter Calculator Formula
Understand the math behind the notch filter calculator. Each variable explained with a worked example.
Formulas Used
Notch Frequency
notch_freq = 1 / (2 * pi * sqrt(l_h * c_f))Variables
| Variable | Description | Default |
|---|---|---|
inductance_mh | Inductance(mH) | 1 |
capacitance_nf | Capacitance(nF) | 10 |
l_h | Derived value= inductance_mh / 1000 | calculated |
c_f | Derived value= capacitance_nf / 1000000000 | calculated |
How It Works
Notch (Band-Reject) Filter
f_notch = 1 / (2pi x sqrt(LC))
A notch filter rejects a narrow band of frequencies while passing all others. The rejection frequency uses the same LC resonance formula.
Worked Example
L=1 mH, C=10 nF to reject interference.
inductance_mh = 1capacitance_nf = 10
- 01f_notch = 1 / (2pi x sqrt(0.001 x 1e-8))
- 02f_notch = 50,329 Hz
Ready to run the numbers?
Open Notch Filter Calculator