Passive RC and LC filters
Evaluate loaded RC, RC–RC, RLC low-pass and LC pi networks with magnitude and phase plots.
Development preview. Check the assumptions below before relying on a result. Calculations run in your browser.
How it calculates
Model: Complex series/parallel impedance reduction includes the finite output load and ladder loading.
Assumptions
- RC-RC has shunt C1 after R1 and shunt C2 after R2. LC pi has shunt C1 after source R1, series L, then shunt C2/load. RLC uses series R1+L, shunt C1/load.
- Ideal L and C; no parasitic losses beyond entered resistors.
Worked example
These are the calculator's default inputs. Change any input above to recalculate.
Inputs
- Topology
- RC low-pass
- Series/source R1
- 1000 Ω
- Second ladder resistor R2
- 1000 Ω
- C1
- 1e-7 F
- C2
- 1e-7 F
- Series inductance
- 0.001 H
- Output load
- 1000000 Ω
- Evaluation frequency
- 1000 Hz
- Sweep start
- 10 Hz
- Sweep end
- 1000000 Hz
Results
- Voltage gain
- -1.4513 dB
- Phase
- -32.1161 degree
- Voltage gain
- 0.846126