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Edith Clarke

Graphical Calculator

Patent No. 1,552,113

Pioneering female electrical engineer Edith Clarke invented a graphical calculator that greatly simplified the calculations necessary to determine the electrical characteristics of long electrical transmission lines. She was known for developing mathematical methods that simplified and reduced the work of electrical engineers.

Clarke worked both at AT&T and General Electric. At AT&T, she assisted NIHF Inductee George Campbell, learning about transmission lines and electrical circuits, and at General Electric, she invented her calculator and other ways to improve the electrical distribution system. After retiring from GE, she was appointed to the faculty of the University of Texas at Austin. Throughout her career, Clarke was often the first in her endeavors, whether the first professionally employed female electrical engineer in the United States, the first female full voting member of what would become IEEE, or the first full time female professor of electrical engineering in the country.

Clarke received her B.S. from Vassar College and her M.S. from MIT. Between 1923 and 1945, she published 18 technical papers, including two award-winning ones. She was an authority on the manipulation of hyperbolic functions, equivalent circuits, graphical analysis, and electric power systems; she also worked on the design and building of hydroelectric dams in the West.

Patent Number

Born: February 10, 1883

Died: October 29, 1959


Patent No. 1,552,113

Issued September 1, 1925

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