Percy Spencer Melts a Chocolate Bar, Invents the Microwave Oven – New England Historical Society

Percy Spencer had only a fifth-grade education, but that didn ’ triiodothyronine stop him from earning patents crucial to winning World War II – and to cooking dinner in minutes. He was the fourth person hired at a modern company called Raytheon in Cambridge, Mass. He had an scabies to learn and the temper of a talk through one’s hat elk in mating temper. In a 1958 Reader ’ south Digest article, an MIT scientist suggested Spencer benefited from his miss of school :

The educate scientist knows many things won ’ deoxythymidine monophosphate work. Percy doesn ’ thymine know what can ’ metric ton be done .


Percy Spencer was born July 19, 1894, in Howland, Maine. His father died when he was 18 months previous, and his mother sent him to live with his aunt and uncle. His uncle died when he was seven. Young Percy and his widow aunt traveled around New England, earning money from her weaving and whatever odd job he could pick up. He left school after the fifth degree and got a job in a spool factory when he was 12, working from sunrise to sundown. At 16 he learned the owner of a newspaper mill planned to electrify the plant. Intrigued, Percy Spencer applied for one of three job openings as an electrician. He learned about electricity by studying at night and by test and error. In 1912 he read how radio receiver radio operators directed the ship Carpathia to rescue Titanic passengers. He decided he wanted to be one so he joined the Navy, where he learned about radio engineering. “ I just got hold of a lot of textbooks and taught myself while I was standing watch at night, ” he said. He besides taught himself trigonometry, tartar, chemistry, physics, metallurgy and radio receiver technology. The Navy discharged him honorably at the end of World War I .


Vannevar Bush and Laurence Marshall, two engineers who ’ five hundred roomed together at Tufts University, had started the american Appliance Company in Cambridge, Mass. They aimed to manufacture a refrigerator with no moving parts. The estimate didn ’ deoxythymidine monophosphate work, indeed in 1924 they decided to make S flatulence rectifier vacuum tubes invented by Charles G. Smith, their first gear employee. The rectifier tube eliminated the need for two batteries to operate a radio. The tube transformed radios into low-cost family appliances from complicated hobbyist experiments. soon, every home had to have one. percy spencer raytheon In August 1924 Marshall and Bush renamed the company Raytheon, a portmanteau word mean ‘ beam of light from the gods. ’ The company would finally move to an honest-to-god push button factory in Waltham, Mass. Percy Spencer was hired as Raytheon ’ s fourth employee in 1925. He went to work making vacuum tubes. By 1939, he was a top-flight technical in vacuum tube design. He was sol adept at it he “ could make a knead tube out of a sardine can, ” said a Massachusetts Institute of Technology physicist .


Spencer did a bunch for Raytheon. His expertness in radio tubes helped win a government sign to produce radar fight equipment for MIT ’ s Radiation Laboratory. A priority for the military was the production of magnetrons, which generated the radio signals used in radar.

Raytheon was producing 17 magnetrons a day. Percy Spencer figured it was faster to stamp and solder magnetron parts than to machine them, and production rose to 2,600 a day. Raytheon produced 80 percentage of the magnetron tubes used in U.S. and British radar during the war. U.S. bombers were equipped with his radar sets, knock-down adequate to spot U-boat periscopes from the breeze. During World War II, Spencer ’ mho staff at Raytheon increased to 5,000 from 15. For his function, the Navy awarded him the Distinguished Public Service Award .

Percy Spencer Pops Popcorn

One day at knead in 1945 Spencer was standing future to an active magnetron when a candy prevention in his air pocket melted. Intrigued, he sent out for unpopped popcorn. When it popped in front of the magnetron, he realized that microwaves could cook food. From there he went on to develop the microwave oven by adding a high density electromagnetic field generator to an enclosed alloy box. The first microwave oven was 5 ’ 6 ” tall, weighed 750 pounds and cost vitamin a a lot as $ 3,000. It was excessively boastful, excessively expensive and excessively chilling for consumers to use, but found its manner to restaurants, railroad track cars and ocean liners .

Commercial Failure

“ The early microwave ovens, and we had one, were equally big as a refrigerator, would take twenty minutes to warm up before you could cook anything, but they were 10 times more potent than anything you can buy nowadays, so a potato was cooked in thirty seconds, ” said Rod Spencer, Percy ’ s grandson. Percy Spencer insisted Raytheon ’ mho chef cook with the oven. But its shortcomings were apparent : It didn ’ t brown meat or crisp french fries. The fudge depart. “ The microwave oven finally became known as Raytheon ’ randomness largest commercial bankruptcy, and the reason why was that like indeed many other failures, they saw the aplomb technology but they didn ’ thyroxine understand the market, ” Rod Spencer said . Ad for a microwave oven, ca 1959 ad for a microwave oven, ca 1959 Microwave ovens finally shrunk down to countertop size. In 1967 the first relatively low-cost microwave oven went for sale at $ 495. By 1975 more sold than gas ranges. Percy Spencer received $ 2 for his patent for a microwave oven – the gratuity Raytheon awarded all employees for patents obtained by the ship’s company. Over his life, the thinly educated orphan from Maine earned 300 patents. Percy Spencer died Sept. 8, 1970. This report about Percy Spencer was updated in 2022.