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Leaders in Innovation

How Edith Clarke Solved Equations and Advanced STEM Fields

With Pi Day just around the corner on March 14, math might be on your mind a bit more than usual right now. As you find the ratio of a circle's circumference to its diameter (and maybe have a slice of pie), you could also celebrate what might be mathematicians’ favorite day of the year by using a graphical calculator like the one invented by National Inventors Hall of Fame® Inductee Edith Clarke.


Forging a Path in STEM

Born in Maryland on Feb. 10, 1883, Edith Clarke was one of nine children. Having lost both her parents by the age of 12, Clarke decided to use her inheritance to enroll at Vassar College at age 18, to study both mathematics and astronomy.

After graduating from Vassar in 1908, she taught mathematics and physics at a private school in San Francisco, and at Marshall College in West Virginia. She later studied civil engineering at the University of Wisconsin-Madison and then joined AT&T in 1912. At AT&T she worked as a “computer” — a human calculator supporting engineers as they built the first transcontinental phone line.

Continuing her education at the Massachusetts Institute of Technology, Clarke became the first woman at this school to earn a master’s degree in electrical engineering, making a significant impact on the future of STEM (science, technology, engineering and mathematics) fields.


Making Monumental Calculations

Though she could not initially find work as an engineer, Clarke began working for General Electric (GE) in its Turbine Engineering Department as a supervisor of computers. While working at GE, she invented a graphical calculator — the Clarke Calculator — that greatly simplified and reduced the work of electrical engineers as they determined the characteristics of long electrical transmission lines.

Her invention could solve problems that involved electric current, voltage and impedance in power line transmissions, and it could solve equations with hyperbolic functions 10 times faster than other methods at the time. Clarke filed for a patent on her graphical calculator in 1921, and it was granted in 1925. According to the U.S. Department of Energy, Clarke’s ability to gather data about the power grid contributed to the development of “smart grid” technology.

Also in 1921, while on a leave of absence from GE, Clarke taught physics at the Constantinople Women’s College in Turkey. At that time, she had not been permitted to do engineering work, was kept at a lower professional status and was earning a lower salary than men in the same position. When she returned from Turkey in 1922, however, GE offered her a job as a salaried electrical engineer in its Central Station Engineering Department. Clarke accepted the offer and became the first woman in the country to be employed as an electrical engineer.

In 1926, Clarke became the first woman to present a paper at the annual meeting of the American Institute of Electrical Engineers (AIEE), which later became the Institute of Electrical and Electronics Engineers (IEEE). Additionally, she and two others became the first women to be named AIEE Fellows in 1948.  Clarke also applied her electrical expertise to work on the design and construction of hydroelectric dams in the West Hoover Dam, which still generates power today.

After retiring from GE in 1945, Clarke became the first woman professor of electrical engineering in the nation when she joined the faculty of the University of Texas at Austin in 1947. She continued teaching there for 10 years, until her retirement in 1957.


Meet More Trailblazing Inventors

To learn more about the exceptional creators, innovators and entrepreneurs who have been inducted into NIHF, we invite you to visit our website.

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