PPolySim OS

Root Locus

Turn up the feedback gain and watch a system's poles march across the complex plane — straight toward instability if you push too far.

Root LocusLive

Controls

Presets

The root locus traces where a system's closed-loop poles travel as feedback gain increases. Poles in the left half-plane mean stability; as gain rises they migrate toward the imaginary axis, and crossing it triggers oscillation. Educational tool.

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Data Inspector

Closed-loop poles-2.00, real
Dampingoverdamped
Stabilitystable ✓

Governing equation

Reading this result: Gain K=3 sits below the breakaway value, so both closed-loop poles stay real and negative near -2.00 — the response is overdamped with no oscillation.

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How it works

The root locus plots how closed-loop pole locations change as loop gain varies from zero to infinity. Poles in the left half-plane are stable; as gain increases they move toward and may cross the imaginary axis, marking the onset of sustained oscillation. Educational tool.

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The math, the assumptions, real-world uses, or a code translation — explained for this exact simulation.

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Frequently asked questions

Is this root locus simulator tool really free?
Yes. Root Locus 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.