Steinmetz and the Concept of Phasor: A Forgotten Story

Abstract

The history of the concept of phasor is often neglected when it is introduced in textbooks on circuits. The presentation does not emphasize the historical aspects, which is natural. This paper intends to recover the original and creative way the concept of complex numbers, then almost unknown to engineers, was applied to electric circuits in sinusoidal steady-state. As usual in physics and engineering, the theory of phasor could have been anticipated by earlier researchers, if they had followed their original reasonings. Maxwell and Heaviside had proved the meal, but could not, or were not interested in writing the recipe.