Joseph Slepian (Boston, 11 February 1891 – 19 december 1969) was an American electrical engineer. He is known for contributing to the development of electrical equipment (including the ignitron) and of the underlying mathematical theories.
Slepian, born in Boston, the son of Jewish-Russian immigrants, studied mathematics at Harvard University, where he both his Bachelor (1911) as its Master of Science (1912) obtained. His doctorate in 1913 under professor George Birkhoff was about the thesis: "On the Functions of a Complex Variable Defines by an Ordinary Differential Equation of the First Order and First Degree". In the meantime he also worked at the Boston Elevated Railway.
After receiving his PhD he was allowed as Sheldon fellow postgraduate studies for a year at the University of Göttingen and at the Sorbonne in Paris. In 1915 he returned to the United States and accepted a position as a mathematics professor at Cornell University.
After one year he left the University to join at the Westinghouse Electric Company in East Pittsburgh. At first he worked at the Department of railway traction, but as early as 1917 went to Westinghouse Research Center in Forest Hills where he was head in 1922, in 1926 Deputy Manager-Advisory engineer and in 1938. A position he would retain until his retirement in 1956. Slepian did important work on the Research Centre, in particular in the area of conduction in ionized gases. This led among other things to the invention of the mercury arc valve and usually the betatron (1927).
In 1918 he married Rose Myerson, with whom he had two sons: Robert and David. Both sons followed in the footsteps of their father, Robert at Westinghouse and David at Bell Laboratories. Despite a heart attack in 1951, whereby he was limited in his daily work, he continued to work until 1956.
Slepian wrote over 120 scientific articles and essays and in 1933 he published the book: "Conductivity of Electricity in Gasses" – a compilation of his lectures for Westinghouse Electric. He is – on George Westinghouse after – holder of most patents in Westinghouse: 204.
Slepian was a member of both the American Institute of Engineers (AIEE, 1927) President-elect rial as the Institute of Radio Engineers (IRE, 1945). In 1941, he was elected member of the National Academy of Sciences.
Throughout his long career, he was awarded many important prizes and medals, such as the John Scott Medal (1932), the Westinghouse Order of Merit (1935) and the IEEE Lamme Medal (1942). In 1947 he was awarded the IEEE Edison Medal "For his work on the autovalve lightning arrester, deion circuit breaker, and ignitron". In 1949, he received an honorary doctorate from the Case Institute of Technology and one of the University of Leeds in 1955.