Microwave oven

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Microwave oven

  1. 1. Microwave oven
  2. 2. • Percy Spencer invented the first microwave oven after World War II from radar technology developed during the war. Named the "Radarange", it was first sold in 1947. Raytheon later licensed its patents for a home-use microwave oven that was first introduced by Tappan in 1955, but these units were still too large and expensive for general home use. The countertop microwave oven was first introduced in 1967 by the Amana Corporation, which was acquired in 1965 by Raytheon • In 1947, Raytheon built the "Radarange", the first commercially available microwave oven.It was almost 1.8 metres (5 ft 11 in) tall, weighed 340 kilograms (750 lb) and cost about US$5,000 ($52,273 in today's dollars) each.
  3. 3. • A microwave oven, often colloquially shortened to microwave, is a kitchen appliance that heats food by bombarding it with electromagnetic radiation in the microwave spectrum causing polarized molecules in the food to rotate and build up thermal energy in a process known as dielectric heating. • Microwave ovens heat foods quickly and efficiently because excitation is fairly uniform in the outer 25–38 mm of a dense (high water content) food item.
  4. 4. • A microwave oven heats food by passing microwave radiation through it. Microwaves are a form of non-ionizing electromagnetic radiation with a frequency higher than ordinary radio waves but lower than infrared light.
  5. 5. INTERNAL STRUCTURE
  6. 6. Magnetron • It was with the invention of the cavity magnetron that the waves of a small enough wavelength (microwaves) became possible. The magnetron was originally a crucial component in the development of short wavelength radar during WWII production of electromagnetic . • It is high-powered microwave generator that worked at shorter wavelengths.
  7. 7. Magnetron Tube • The nucleus of the high-voltage system is the magnetron tube . The magnetron is a diode- type electron tube which is used to produce the required 2450 MHz of microwave energy. • It is classed as a diode • A magnetic field imposed on the space between the anode (plate) and the cathode serves as the grid
  8. 8. APPLICATION •Microwave ovens are popular for reheating previously cooked foods and cooking vegetables. •They are also useful for rapid heating of otherwise slowly prepared cooking items, such as hot butter, fats, and chocolate. the oven is used to heat frying-oil and other very oily items (such as bacon), which attain far higher temperatures than that of boiling water.

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