The RMS value is used to quantify the overall “size” of a waveform with a single number. By extension, harmonic amplitudes can be used to describe a complex waveform with just a few non-zero values. Understanding the relationship between an RMS value, harmonic amplitudes, and the total harmonic distortion (THD) of a waveform allows for a faster and more effective power quality investigation when faced with voltage or current distortion problems...