February 10, 1883 - October 29, 1959

Edith Clarke's achievements were in the applications of mathematics to engineering. She was born in Ellicott City, Maryland in 1883, one of nine children. Both her parents died by the time she was twelve and with the money she inherited when she turned 18, she decided to study mathematics and astronomy at Vassar College. She graduated Phi Beta Kappa in 1908, then taught mathematics and physics, first at a private girls' school in San Francisco and then at Marshall College in West Virginia. Wanting to be an engineer, however, Clarke enrolled in the civil engineering program at the University of Wisconsin in 1911. A summer job as a mathematical computing assistant at AT&T changed those plans, though, as she decided to remain full-time at AT&T. One of the first computational tasks she was assigned was to calculate the first seven terms of an infinite series that represented a probability function. Clarke eventually became the manager of a group of women "computers" who made calculations for the Transmission and Protection Engineering Department during World War I. During that time she also studied radio at Hunter College and electrical engineering at Columbia University.

Clarke left AT&T in 1918 to study electrical engineering at MIT in Boston. She earned her master's degree in 1919, the first electrical engineering degree ever awarded to a woman at that institution. Her thesis, supervised by A. E. Kennelly, was entitled "Behavior of a lumpy artificial transmission line as the frequency is indefinitely increased." Upon graduation she accepted a job at General Electric where she worked for the next 26 years, except for two years leave as a professor of physics at the Constantinople Women's College in Turkey.

James Brittain writes that "Edith Clarke's engineering career had as its central theme the development and dissemination of mathematical methods that served to simplify and reduce the time spent in laborious calculations in solving problems in the design and operation of large electrical power systems" [1]. She became an authority on the manipulation of hyperbolic functions, equivalent circuits, and graphical analysis.
In 1926 Clarke became the first woman to present a paper before the American Institute of Electrical Engineers (AIEE). Her paper on "steady-state stability in transmission systems" described a mathematical technique to model a power system and its behavior that allowed engineers to analyze the longer transmission lines then becoming more common. Between 1923 and 1945, Clarke published 18 technical papers. One paper, co-authored by Clarke and published in 1941 in the Transactions of the American Institute of Electrical Engineers, received the National First Paper Prize of the Year award from the AIEE. "This was the first published mathematical examination of transmission lines over 300 miles long, and the first published use of the network analyzer to obtain data" [3]. Clarke also wrote the book *Circuit Analysis of A-C Power Systems* that was published in 1943. A second volume appeared in 1950.

Clarke retired from GE in 1945. Two years later she was appointed a full professor at the University of Texas, becoming the first female professor of electrical engineering in the country. She taught there until 1956.

In 1948 Edith Clarke became the first woman elected as a Fellow of the American Institute of Electrical Engineers (now known as the Institute for Electrical and Electronics Engineers, or IEEE). In 1954 she received the Society of Women Engineers Achievement Award "in recognition of her many original contributions to stability theory and circuit analysis."

- Brittain, James E. "From Computer to Electrical Engineer: The Remarkable Career of Edith Clarke," IEEE Transactions on Education, Vol. E28, No. 4 (November 1985), 184-189.
- Brittain, James E. "Edith Clarke and power system stability", IEEE Industry Applications Magazine, Vol. 9, No. 1 (Jan/Feb 2003), 9-10
- "Clarke, Edith 1883-1959,"
*Contemporary Authors, Scot Peacock, Editor, Gale Research, 1998, 74-75.* - Author Profile at zbMath

Photo Credit: Photo courtesy of the SWE Archives, Walter P. Reuther Library, Wayne State University