Comparator Hysteresis Calculator
Schmitt-trigger thresholds and window from your reference and feedback resistors — kill comparator chatter by design.
Without hysteresis a slow or noisy signal makes the comparator chatter — multiple edges per crossing that destroy counters and ADC triggers. Size the window ≥ 2× the peak-to-peak noise. Both thresholds sit slightly ABOVE Vref (by the R1/R2 scaling) — recentre by lowering Vref if symmetry matters. With open-drain parts the pull-up value joins R2 in the math.
Comparator Hysteresis Calculator computes the upper/lower thresholds and window of a Schmitt-trigger comparator — free, instant and private in your browser. Designers of threshold detectors, battery cutoffs and anything reading slow noisy signals use it to skip the datasheet algebra: type your numbers, read the answer with the substituted formula shown step by step, and share an exact permalink of the calculation.
About Comparator Hysteresis Calculator
Comparator Hysteresis Calculator computes the upper/lower thresholds and window of a Schmitt-trigger comparator using the standard engineering relation: ΔV = (Voh − Vol)·R1/R2, thresholds straddling Vref·(R1+R2)/R2. Worked live: 10 kΩ / 1 MΩ around a 2.5 V reference on a 5 V comparator gives a clean 50 mV window. The result recalculates on every keystroke, the worked-example panel shows your numbers substituted into the formula, and the Copy permalink button encodes the inputs in the URL so a colleague opens exactly your calculation. Everything runs client-side — nothing you type leaves your device.
How to use Comparator Hysteresis Calculator
- 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
- 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
- 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.
Why use Comparator Hysteresis Calculator?
- ✓Implements the real formula — ΔV = (Voh − Vol)·R1/R2, thresholds straddling Vref·(R1+R2)/R2 — with the substitution shown, not a black box
- ✓Built for designers of threshold detectors, battery cutoffs and anything reading slow noisy signals
- ✓Copy result and permalink buttons — share the exact calculation in a README, forum answer or design review
- ✓100% free, no sign-up, runs entirely in your browser (works offline once loaded)
Frequently asked questions
How do you calculate comparator hysteresis?+
The upper/lower thresholds and window of a Schmitt-trigger comparator follows ΔV = (Voh − Vol)·R1/R2, thresholds straddling Vref·(R1+R2)/R2. For example, 10 kΩ / 1 MΩ around a 2.5 V reference on a 5 V comparator gives a clean 50 mV window. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
Why does my comparator output chatter at the threshold?+
A slow or noisy input recrosses the single threshold many times per transition, producing bursts of edges that wreck counters and MCUs. Hysteresis separates the up and down thresholds so one crossing = one edge. Size the window ≥ 2× the peak-to-peak noise.
Can I add hysteresis to an op-amp used as a comparator?+
The same positive-feedback math works, but op-amps make poor comparators: recovery from saturation is slow and some (rail-to-rail bipolar inputs) misbehave when overdriven. Real comparators (LM393 class) switch in nanoseconds — use one, plus this network.
Is the Comparator Hysteresis Calculator free and private?+
Yes — completely free with no sign-up or usage limits, and it runs entirely in your browser: the values you enter are never uploaded or stored on a server.
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