Cavity magnetron

device for generating microwaves

The cavity magnetron is a high-powered vacuum tube that makes microwaves using the interaction of a stream of electrons with a magnetic field. Electrons pass by holes (cavities), and the resonance creates microwaves, like blowing air on a flute creates sound (sound waves) of a certain pitch.[1] The 'resonant' cavity magnetron type of the earlier magnetron tube was invented by John Randall and Harry Boot in 1940.[2] The high power of pulses from the cavity magnetron made centimetre-band radar practical. Shorter wavelength radars allowed the finding of smaller objects. The small cavity magnetron tube made the size of radar sets much smaller[3] so that they could be put into in aircraft[4] and ships used to find submarines.[3] At present, cavity magnetrons are commonly used in microwave ovens and in various radar applications.[5]

Magnetron with section removed (magnet is not shown)
Complete microwave oven magnetron, with magnet and heatsink

References Edit

  1. "How do magnetrons work?". Explain that Stuff. 28 August 2009. Retrieved 2020-05-20.
  2. "The Magnetron". Bournemouth University. 1995–2009. Retrieved 23 August 2009.
  3. 3.0 3.1 Schroter, B. (Spring 2008). "How important was Tizard's Box of Tricks?" (PDF). Imperial Engineer. 8: 10. Archived from the original (PDF) on 2011-06-17. Retrieved 2009-08-23.
  4. "Who Was Alan Dower Blumlein?". Dora Media Productions. 1999–2007. Archived from the original on 7 September 2009. Retrieved 23 August 2009.
  5. Ma, L. "3D Computer Modeling of Magnetrons." University of London Ph.D. Thesis. December 2004. Accessed 2009-08-23.