Calculator Inputs
Example Data Table
| Order | Label | Magnitude |
|---|---|---|
| 1 | Fundamental | 230.00 |
| 3 | 3rd Harmonic | 12.00 |
| 5 | 5th Harmonic | 18.00 |
| 7 | 7th Harmonic | 9.00 |
| 9 | 9th Harmonic | 6.00 |
| 11 | 11th Harmonic | 4.00 |
| 13 | 13th Harmonic | 3.00 |
This sample illustrates one fundamental component and several odd harmonics commonly reviewed in power quality checks.
Formula Used
Total Harmonic Distortion:
THD = √(V₂² + V₃² + ... + Vn²) / V₁ × 100
Here, V₁ is the fundamental magnitude, and higher-order terms represent harmonic magnitudes.
Harmonic RMS:
Harmonic RMS = √(V₂² + V₃² + ... + Vn²)
Total RMS:
Total RMS = √(V₁² + V₂² + V₃² + ... + Vn²)
Distortion Factor:
DF = 1 / √(1 + THD²)
These expressions help quantify waveform purity, compare designs, and inspect whether distortion stays within acceptable engineering limits.
How to Use This Calculator
- Choose whether you are analyzing voltage, current, or power.
- Enter the fundamental magnitude of the waveform.
- Input harmonic magnitudes from the 2nd through 13th order.
- Set the base system frequency and desired THD limit.
- Submit the form to view THD, total RMS, compliance, and charted harmonics.
- Download the results as CSV or print them as a PDF report.
Frequently Asked Questions
1. What does harmonic distortion mean?
Harmonic distortion measures how much a waveform differs from a pure sine wave because of added frequency components at integer multiples of the fundamental frequency.
2. Why is THD important in engineering?
THD helps evaluate power quality, equipment stress, waveform purity, heating losses, control instability, and possible interference in electrical and electronic systems.
3. What is considered a good THD value?
Lower values are generally better. Many systems aim near or below 5%, but acceptable limits depend on standards, equipment sensitivity, and application requirements.
4. Can I use this for current harmonics?
Yes. Select current as the signal type and enter the fundamental current plus each harmonic current magnitude to estimate current distortion.
5. Does this calculator use RMS values?
The formulas are based on RMS relationships. The basis selector is included for reporting context, but consistent units across all inputs remain essential.
6. Why are odd harmonics often larger?
Many nonlinear loads and converter topologies naturally generate stronger odd harmonics because of waveform symmetry and switching behavior.
7. What does the dominant harmonic show?
It identifies the harmonic order with the largest magnitude, helping you locate the most influential distortion component in the waveform.
8. Can I save the report?
Yes. Use the CSV button for spreadsheet analysis or the PDF button to print the current results page as a report.