Heinrich Rudorf Hertz (1857-1894), a German experimental physicist,
demonstrated that electromagneticwaves obey the same fundamental laws
as light. Hiswork confirmed James Clerk Maxwell's celebrated 1864 theory
and prediction that such waves existed.
Hertz was born into a prosperous family in Hamburg, Germany. He attended
the University of Berlin and did his doctorate under the prominent physicist
Hermann von Helmholtz. He became a professor at Karlsruhe, where he began
his quest for electromagnetic waves. Hertz successfully generated and
detected electromagnetic waves; he was the first to show that light is
electromagnetic energy. In 1887, Hertz noted for the first time the photoelectric
effect of electrons in a molecular structure. Although Hertz only lived
to the age of 37, his discovery of electromagnetic waves paved the way
for the practical use of such waves in radio, television, and other communication
systems. The unit of frequency, the hertz, bears his name.
Charles Proteus Steinmetz (1865-1923), a German-Austrian mathematician
and engineer, introduced the phasor method (covered in this chapter) in
ac circuit analysis. He is also noted for his work on the theory of hysteresis.
Steinmetz was born in Breslau, Germany, and lost his mother at the age
of one. As a youth, he was forced to leave Germany because of his political
activities just as he was about to complete his doctoral dissertation
in mathematics at the University of Breslau. He migrated to Switzerland
and later to the United States, where he was employed by General Electric
in 1893. That same year, he published a paper in which complex numbers
were used to analyze ac circuits for the first time. This led to one of
his many textbooks, Theory and Calculation of ac Phenomena, published
by McGraw-Hill in 1897. In 1901, he became the president of the American
Institute of Electrical Engineers, which later became the IEEE.
