Total Harmonic Distortion Calculator
Calculate THD from the amplitudes of harmonic components relative to the fundamental frequency.
V
V
V
V
V
THD
2.567 %
THD-31.8 dB
RSS of Harmonics0.0257 V
THD vs Fundamental Amplitude
What is Total Harmonic Distortion?
THD measures the ratio of harmonic content to the fundamental, indicating how much a device distorts a pure signal.
Formula
THD = sqrt(V2^2 + V3^2 + V4^2 + V5^2 + ...) / V1 x 100%
Where V1 is the fundamental and V2, V3... are harmonic amplitudes.
Quality Benchmarks
Example Calculation
Fundamental at 1.0 V with harmonics at 0.02, 0.015, 0.005, 0.003 V.
- 01RSS = sqrt(0.02^2 + 0.015^2 + 0.005^2 + 0.003^2)
- 02= sqrt(0.0004 + 0.000225 + 0.000025 + 0.000009) = sqrt(0.000659)
- 03= 0.02567 V
- 04THD = 0.02567 / 1.0 x 100 = 2.567%
- 05THD dB = 20 x log10(0.02567) = -31.8 dB
Frequently Asked Questions
Learn More
Ohm's Law Guide
A complete guide to Ohm's Law. Learn the relationship between voltage, current, and resistance, with practical examples, the power triangle, and circuit analysis tips.