PPolySim OS

Active Filter (Bode Plot)

Filters keep the frequencies you want and reject the rest. Set the cutoff and order and watch the Bode magnitude curve roll off.

Active Filter (Bode Plot)Live

Controls

Presets

A filter passes some frequencies and blocks others. The cutoff fc = 1/(2πRC) is where the response falls 3 dB; beyond it the magnitude rolls off at 20 dB per decade per order — steeper filters cut harder. Educational tool.

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Data Inspector

Cutoff frequency1.0 kHz
Roll-off40 dB/decade
At 10×fc-40 dB

Governing equation

Reading this result: The −3 dB cutoff sits at 1.0 kHz, where the low-pass response begins to roll off. Order 2 sets the steepness at 40 dB/decade — a gentle slope that eases into the stopband with minimal ringing. Raising the order steepens the roll-off while adding phase lag around the cutoff.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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How it works

A filter passes a band of frequencies and attenuates the rest. The cutoff fc = 1/(2πRC) marks the −3 dB point; beyond it the magnitude falls at 20 dB per decade per filter order, so higher-order filters cut more sharply at the cost of complexity. Educational tool.

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Frequently asked questions

Is this active filter bode plot tool really free?
Yes. Active Filter (Bode Plot) runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.
Do I need to install anything?
No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.
Can I save or share my simulation?
Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.
How accurate are the results?
The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.