Analogue Filter Calculator

Calculate analogue filter parameters directly on this page.
Note: Graph colours Red = Magnitude, Blue = Phase. Complex frequency: s = σ + jω = σ + j·2π·fo.

Passive Filters

RC Circuits

[a] [b] [c]
Bode Plot
Low-pass [a]
Transfer Function
Cut-off Frequency
Ω
F
Hz
s  
RL Circuits

[a] [b] [c]
Bode Plot
High-pass [a]
Transfer Function
Cut-off Frequency
Ω
H
Hz
LC Circuits

[a] [b] [c]
Bode Plot
Resonant (peak) [a]
Transfer Function
Cut-off Frequency
H
F
Hz

Active Filters

OpAmp Low-pass/High-pass Circuits

[a] [b]
Bode Plot
Low-pass [a]
Transfer Function
Gain Cut-off Frequency
Ω
F
Hz
OpAmp Circuit with Complex Poles
Bode Plot
Band-pass with Q-factor
and gain, G
Transfer Function
R1 = Q/G
R2 = Q/(2 · Q2 - G)
R3 = 2 · Q
Resistor Scaling Factor = 1/(2 ·π· f0 · C)
Hz
F
Ω
Ω
Ω