Edith Clarke (10 February 1883 – 29 October 1959) was an electrical engineer and a professor at the University of Texas at Austin. She was the first woman employed as an electrical engineer in the United States, as well as the country's first female professor of electrical engineering.
Clarke studied mathematics and astronomy at Vassar College, receiving an A.B. in 1908. She briefly taught mathematics and physics at a private school in San Francisco and at Marshall College. She then spent some time studying civil engineering at the University of Wisconsin–Madison, but left to become a "computer" at AT&T in 1912. She computed for George Campbell, who applied mathematical methods to the problems of long-distance electrical transmissions. While at AT&T, she studied electrical engineering at Columbia University by night.
In 1918, Clarke enrolled at the Massachusetts Institute of Technology, and the following year she became the first woman to earn an M.S. in electrical engineering from MIT. Despite her degree, she was unable to be hired as an engineer. Instead, she went to work for General Electric as a supervisor of computers in the Turbine Engineering Department. In her spare time, she invented the Clarke calculator, a simple graphical device that solved equations involving electric current, voltage and impedance in power transmission lines. The device could solve line equations involving hyperbolic functions ten times faster than previous methods. She applied for a patent on the device in 1921.
In 1921, still unable to obtain a position as an engineer, she left GE to teach physics at the Constantinople Women's College in Turkey. The next year, GE finally became aware of her value and re-hired her as an engineer in the Central Station Engineering Department.
Unlike many of her colleagues of the time, Clarke was well versed in higher mathematics and aware of its importance to electrical engineering, particularly to the increasing complexity and interconnectedness of power systems. In 1926, as the first woman to deliver a paper at the American Institute of Electrical Engineers' annual meeting, she showed the use of hyperbolic functions for calculating the maximum power that a line could carry without instability. Two of her later papers won awards from the AIEE.
Clarke retired from General Electric in 1945. In 1947, she joined the faculty of the Electrical Engineering Department at the University of Texas at Austin. She taught for ten years, and retired in 1957.
In 1948, Clarke was the first female Fellow of the American Institute of Electrical Engineers. In 1954, she received the Society of Women Engineers Achievement Award.