Mathematician and electrical engineer German, naturalized American, born on April 9, 1865 in Breslau, Prussia (today Wroclaw, Poland), and died on October 26, 1923 in Schenectady, New York State, whose alternating current studies facilitated the use of this type of industrial power.

Born Karl August Rudolf Steinmetz, a physical deformity - corcovado era - made him take refuge in textbooks in his youth, where he demonstrated an unusual ability in mathematics, physics and classical literature. After graduating with full honors at the local Gymnasium he entered the University of Breslau in 1883, where he started political activity in a club of Socialist students who later joined the German Social Democratic Party. At the time of a RAID in which were captured several of his comrades, took charge of the management of the newspaper of the party, the voice of the people, whose editorials were branded arsonists by authorities and irritated the police to the point where Steinmetz was forced to leave the country.

After a brief stay in Zurich, he emigrated to the United States as a stowaway on a freighter, and shortly after arriving got a job in a small electric company, owned by his compatriot Rudolf Eickemeyer in Yonkers, situated in the State of New York. To achieve U.S. citizenship he Americanized his name and introduced as second the Nom de guerre of his Socialist days, that that signed caustic editorials.

In this company, and with the blessing of his employer, assembled a small laboratory where he did most of his discoveries, among which the study of the phenomenon of hysteresis is located in electromagnets (1892), phenomenon giving rise to losses of energy in the form of heat. His study allowed that electrical engineers design each electromagnet knowing in advance what were its energy losses, remarkable progress if it is thought that previously it was only possible to measure the losses once built the device properly. A year later, when the company was absorbed by the General Electric Co., succeeded in that you respect his position and his laboratory, and developed a mathematical theory that allowed the calculations in AC circuits, which facilitated that changed the grids DC existing previously by the much cheaper and easily conducive AC. That same year published a theory about the so-called transient currents, electric currents that appear in devices once have been disconnected and that very often produce irreparable damage on machines. These phenomena are often accompanied by the emission of light. After designing and constructing a generator able to provide downloads of 10,000 amps to 100,000 volts for a thousandth of a second, true artificial rays with those who study this kind of phenomena, he published a work about the transmission of waves in the air that has been, as almost everything what it published, as a classic.

These works, because of the dryness of its rigorous mathematical treatment, were understood by very few members of Congress attended, although its importance as a theoretical prediction tool escaped anyone in electrical designs. All this led him to simplify the mathematical language of his articles, often using a simple symbolic notation, divide them into more easily digestible chapters and edit a math book aimed at electrical engineers, in such a way that their methods of calculation were widespread in all Guild.

They say that Henry Ford called him to investigate what happened you to a generator of its factory which did not work correctly. After spending two days examining its operation, called a staircase and a chalk, climbed to the generator made a mark on it and ordered removed exactly that point sixteen turns of the coil. After making the arrangement and check that it worked properly, it extended an invoice for ten thousand dollars to Mr Ford. When asked he detailed invoice, wrote in a paper: "chalk mark: 1 dollar." Know where to put it: 9999 ".

Steinmetz was President of the American Institute of electrical engineers, Member of the Academy of Arts and Sciences and doctor honoris causa of the Union College of Schenectady. His works include General lectures on electrical engeneering (1909), Theory and calculation of alternating current phenomena (1909), Theory and calculation of transient electric phenomena (1909), Radiation light and illumination (1911), Elementary lectures on electric waves and discharges impulses (1912), Theory and calculation of electrical apparatus (1917), Theory and calculation of electric circuits (1917) and Engineering mathematics (1917).