Inventor Spotlight: Percy L. Spencer

This month, C4IP is honoring Percy L. Spencer (1894-1970), whose invention of the microwave oven revolutionized how people cook and eat around the world.

  • Despite never completing elementary school, Spencer taught himself radio engineering while serving in the U.S. Navy during World War I, and subsequently became a successful engineer at Raytheon Corporation.
  • While working to advance radar technology, Spencer realized that the magnetron vacuum tubes he was working with could also be used to heat food — and used that knowledge to create the first microwave oven, which he patented in 1950.
    • Spencer ultimately received over 100 patents over the course of his career.
  • Spencer’s invention has become a staple in kitchens across America, with over 90% of U.S. households owning a microwave oven today.
    • Thanks to the ubiquity of the microwave, industries like frozen food have also seen significant growth, with roughly two-thirds of Americans consuming frozen food weekly.
  • The microwave oven has had an enormous economic impact: In 2024, the global market for microwave ovens was estimated at over $10 billion, with more than 80 million microwaves being sold each year.
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