Waveform Form Factor
FF = Vrms / Vavg
Quick answer
This calculator solves FF = Vrms / Vavg for Form Factor. With RMS Value 12 V, Average Value 26.4 V, the result is 0.4545. It solves in 3 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
The form factor of a waveform is the ratio of its RMS value to its average (rectified mean) value, and it characterises the shape independent of amplitude. A pure sine wave has a form factor of about 1.11; a square wave is 1.0; sharper, peakier waveforms have larger form factors. It is used to relate average-reading meters to true RMS and to characterise rectified outputs.
Variables
- FF — Form factor (dimensionless)
- Vrms — RMS value of the waveform (V)
- Vavg — Average (rectified mean) value (V)
Practical Notes
Average-responding AC meters are calibrated assuming a sine (×1.11); they misread non-sinusoidal signals. Together with the crest factor (peak/RMS) the form factor describes a waveform’s shape.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| FF | Form Factor | — | — |
| Vrms | RMS Value | V | pV, nV, µV, mV, V, kV |
| Vavg | Average Value | V | pV, nV, µV, mV, V, kV |
Step by step
- 1. What you know: RMS Value 12 V, Average Value 26.4 V
- 2. The relation: FF = Vrms / Vavg
- 3. Substitute: Vrms = 12 V, Vavg = 26.4 V
- 4. Result: Form Factor = 0.4545
Worked examples
Minimum range
Given: RMS Value 0.33 V, Average Value 0.726 V
Result: Form Factor = 0.4545
Low range
Given: RMS Value 3.3 V, Average Value 7.26 V
Result: Form Factor = 0.4545
Typical
Given: RMS Value 12 V, Average Value 26.4 V
Result: Form Factor = 0.4545
High range
Given: RMS Value 0.23 kV, Average Value 0.506 kV
Result: Form Factor = 0.4545
Maximum range
Given: RMS Value 2.3 kV, Average Value 5.06 kV
Result: Form Factor = 0.4545
Solving for each variable
Solve for Form Factor
RMS Value 0.33 V, Average Value 0.726 V → 0.4545
Solve for RMS Value
Form Factor 0.025, Average Value 0.726 V → 18.15 mV
Solve for Average Value
Form Factor 0.025, RMS Value 0.33 V → 13.2 V
How Form Factor changes with RMS Value
| RMS Value (input) | Form Factor (result) |
|---|---|
| 1.2 V | 0.04545 |
| 3 V | 0.1136 |
| 6 V | 0.2273 |
| 9 V | 0.3409 |
| 12 V | 0.4545 |
| 18 V | 0.6818 |
| 24 V | 0.9091 |
| 48 V | 1.818 |
| 84 V | 3.182 |
| 120 V | 4.545 |
Embed this calculator
Paste this into any page. It keeps working when this page updates, and credits the source.
<iframe src="https://vbatpower.com/embed/form-factor/" width="100%" height="460" style="border:1px solid #1f2a37;border-radius:12px" loading="lazy" title="Waveform Form Factor"></iframe>
<p><a href="https://vbatpower.com/formulas/form-factor/">Waveform Form Factor</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate Waveform Form Factor?
Use FF = Vrms / Vavg. With RMS Value 12 V, Average Value 26.4 V, Form Factor works out to 0.4545.
What is the formula for Waveform Form Factor?
The formula is FF = Vrms / Vavg. The form factor of a waveform is the ratio of its RMS value to its average (rectified mean) value, and it characterises the shape independent of amplitude.
How do you find RMS Value when you know the other values?
Rearrange for RMS Value: with Form Factor 0.025, Average Value 0.726 V, RMS Value is 18.15 mV.
How do you find Average Value when you know the other values?
Rearrange for Average Value: with Form Factor 0.025, RMS Value 0.33 V, Average Value is 13.2 V.
Related Concepts
All AC Circuits formulas →Need more features?
Save calculations, import telemetry data, simulate battery discharge, and collaborate with your team.
Try the App