cavity magnetron
Datecirca 1943
Inventory NumberVT1196
ClassificationMagnetron
Subject
Maker
Western Electric Company
1869 - 1995
Cultural Region
Place of Origin
Dimensions15 × 8.3 × 8.3 cm (5 7/8 × 3 1/4 × 3 1/4 in.)
Material
DescriptionWestern Electric model No. 725A magnetron. A black cylindrical cavity with one flat side and many cooling surfaces. On one side is a glass vessel with two electrodes that connect to wires which enter the metallic cavity. At a right angle to it from the cavity comes out long tube with an open end that is connected to a tube with a rectangular cross-section. Produced 3 cm microwaves.
Signedunsigned
FunctionA magnetron is a type of vacuum tube designed to produce microwaves. As other tubes, it has a heated cathode which is placed on the axis of the cylindrical cavity. The anode is constituted by the inner walls of the cavity. The main cavity is subdivided into further circular cavities whose size determines the output wavelength of the tube.
The magnetron works with an attached strong magnet (missing) such that the electrons emitted by the cathodes are deflected by a magnetic field instead of reaching the anode directly. This deflection produces electromagnetic radiation, with the small cavities favoring the particular frequencies that the magnetron is designed to produce. The resulting microwaves leave the magnetron through the long tube, called a waveguide.
The glass part of the magnetron holds the fillament that heats the cathode, so it needs to be of a nonconducting material, whereas the main cavity is heated up during operation and needs to irradiate excess heat, hence the color and many fins.
This model was used in Philco AN/APS-15 bombing radar and similars. Over 300,000 were made.
The magnetron works with an attached strong magnet (missing) such that the electrons emitted by the cathodes are deflected by a magnetic field instead of reaching the anode directly. This deflection produces electromagnetic radiation, with the small cavities favoring the particular frequencies that the magnetron is designed to produce. The resulting microwaves leave the magnetron through the long tube, called a waveguide.
The glass part of the magnetron holds the fillament that heats the cathode, so it needs to be of a nonconducting material, whereas the main cavity is heated up during operation and needs to irradiate excess heat, hence the color and many fins.
This model was used in Philco AN/APS-15 bombing radar and similars. Over 300,000 were made.
American Ever Ready Company
Date: circa 1930
Accessories: red cardboard cylinder case
Object number: VT5201
Rudolph Koenig
Date: 1865-1890
Object number: 1997-1-0919
Walter L. Brown
Date: 1947-1951
Accessories: spectrometer magnet and tripod (RS0326); mount parts (RS0326b and rs0326c)
Object number: RS0326a
