5th Order RC Filter Calculator

This page shows a cascaded RC low-pass filter for audio amplifier power supplies, with up to 5 filter sections, see the diagram below. A cascaded RC filter is much more effective than a single filter. This page computes the frequency response from 1 Hz. to 100 kHz. (under resistive load). You can also see the filter's inrush current that will be presented to the previous stage of your power supply (rectifier, etc.).

Filter stages
Stage
R (Ω)
C (µF)
1
2
3
4
5
Load
Load resistance
3000 Ω
Total series R
500.00 Ω
DC voltage drop
50.00 V
Output voltage
250.00 V
Total R dissipation
5000.0 mW
Max stage dissipation
1000.0 mW
Frequency response

Dashed red line marks −3 dB. X axis is logarithmic.

Schematic
R1C1R2C2R3C3R4C4R5C5V in +V out +V in −V out −
Inrush current

Step response: 300 V applied at t = 0, capacitors initially discharged.

Peak current: 3.000 A

Model: ideal voltage source, five cascaded R-then-C stages, resistive load RL = V / I. Stage loading is included via ABCD-matrix cascade.