All about Best Microwave Oven Buying Guide – Consumer Reports Nevertheless, the main heating result of all types of electromagnetic fields at both radio and microwave frequencies takes place through the dielectric heating impact, as polarized molecules are impacted by a quickly alternating electrical field. The development of the cavity magnetron enabled the production of electromagnetic waves of a small enough wavelength (microwaves). In 19371940, a multi-cavity magnetron was constructed by the British physicist Sir John Turton Randall, FRSE, together with a group of British colleagues, for the British and American military radar installations in World War II. A more high-powered microwave generator that worked at much shorter wavelengths was required, and in 1940, at the University of Birmingham in England, Randall and Harry Boot produced a working model. Sir Henry Tizard traveled to the U.S. in late September 1940 to use the magnetron in exchange for their monetary and commercial aid (see Tizard Mission). An early 6 kW version, integrated in England by the General Electric Business Research study Laboratories, Wembley, London, was offered to the U.S. federal government in September 1940. Contracts were awarded to Raytheon and other business for the mass production of the magnetron. Microwave, several from the 1980s In 1945, the heating result of a high-power microwave beam was mistakenly found by Percy Spencer, an American self-taught engineer from Howland, Maine. Used by Raytheon at the time, he noticed that microwaves from an active radar set he was working on started to melt a chocolate bar he had in his pocket. To verify his finding, Spencer created a high density electro-magnetic field by feeding microwave power from a magnetron into a metal box from which it had no other way to leave. When food was put in package with the microwave energy, the temperature level of the food rose quickly. On 8 October 1945, Raytheon submitted a United States patent application for Spencer’s microwave cooking procedure, and an oven that heated food utilizing microwave energy from a magnetron was quickly put in a Boston dining establishment for screening. It was practically 1.8 metres (5 ft 11 in) high, weighed 340 kgs (750 lb) and cost about US$ 5,000 ($ 57,000 in 2019 dollars) each. It took in 3 kilowatts, about 3 times as much as today’s microwave ovens, and was water-cooled. The name was the winning entry in a staff member contest.
All about Best Microwave Oven Buying Guide – Consumer Reports