Resonance Bandwidth Calculator

How the result is calculated

This page evaluates bandwidth = f₀ ÷ Q. The participating entries are Resonant frequency and Quality factor.

Using the loaded examples gives 500.00 Hz. Your saved case should identify where each entry came from.

Estimate half-power bandwidth from quality factor. The resonant frequency step is handled by Resonant Frequency Calculator.

Values this page needs

Keep distorted-waveform measurements separate from sine-wave assumptions. Nameplate and meter values are not interchangeable unless they describe the same condition.

A denominator entry cannot be zero. Use the displayed unit for every field and document conversions separately. If you also need loaded output voltage, continue with Loaded Voltage Divider Calculator.

Resonant frequency

Default example: 10000 Hz. Enter resonant frequency in Hz.

Quality factor

Default example: 20. Enter quality factor.

Applying the result

Read Bandwidth as the outcome of this equation, not as automatic equipment approval. Compare it with the applicable line-to-line or line-to-neutral limit.

A result without its source conditions is difficult to compare or audit. For the companion output voltage calculation, open Voltage Divider Calculator.

What the formula leaves out

The symmetric limits are a narrow-band approximation.

Additional checks may be needed for harmonics, phase imbalance, saturation, and nonsinusoidal current. Test an additional scenario when an omitted effect has a plausible range.

Record frequency, waveform, phase arrangement, and whether voltage is line or phase.

A second scenario

Change Resonant frequency from 10000 Hz to 12000 Hz as the sole changed variable. The two results are 500.00 Hz to 600.00 Hz.

This isolates one variable; a real system may change several at once.

Documenting the calculation

Document resonant frequency and quality factor with bandwidth. Keep enough context to reproduce the result later.

Pass bandwidth without rounding when it becomes another input. Apply standard sizes only after all checks are complete.

A practical checking sequence

Review resonant frequency and the remaining entries as one case. If one value belongs to another temperature, load, or time period, separate the scenarios.

After calculating bandwidth, compare its magnitude with the applicable line-to-line or line-to-neutral limit. An independent order-of-magnitude check can reveal a misplaced decimal or unit prefix.

Keep a baseline and vary the least certain measurement first. A separate analysis may be needed for startup transients, resonance, and measurement bandwidth.

Questions about Resonance Bandwidth