# Why Distortion Factor (g) is Xo1/Xor and not Xor/Xo1..?

In power electronic convertors (rectifiers) we measure nonlinearities injected into the system by means of

1) Distortion factor(g) :

g = Io1/Ior { fundamental component / rms component }

2) Total Harmonic Distortion (THD) :

THD = √[(1/g^2)-1]

Since we convert g it into (1/g) "rms/fundamental" in measuring the deviation or increase from refernce ( ideal fundamental contions ) ie, THD.

why g is not being expressed as "rms/fundamental" directly and instead as "fundamental/rms" ?

I would like to know the meaning behind "fundamental/rms" format ie, g being measured and expressed as factor of decrease that is required to produce the desired ideal condition (fundamental).

Thanks.