Video camera tube facts for kids
The video camera tube was a type of vacuum tube used to capture television images between the 1930s and 1980s.
A video camera tube uses a lens to focus the image on a photoelectric material (a material which emits electrons when light hits it) housed at the front of a glass tube.
An electron gun at the back of the tube, like those used in a cathode ray tube, fires electrons at the material. When the photoelectric material is hit with brighter light, it produces more electrons, which cause more of the electrons fired by the electron gun to bounce back.
By measuring the number of electrons which bounced back, the video camera tube is able to tell how bright each part of the image is, and create a signal suitable for display on a cathode ray tube.
Related pages
Images for kids
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A display of a variety of early experimental video camera tubes from 1954, with Vladimir K. Zworykin who invented the iconoscope
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Farnsworth image dissector tube from 1931
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Zworykin holding an iconoscope tube
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Dark halo around bright rocket flame in television of John Glenn's liftoff of Mercury-Atlas 6 in 1962
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Schematic of vidicon tube.
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The electron gun from an RCA Vidicon camera tube.
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Schematic of a Plumbicon tube. (This image is schematic, not to scale; a Plumbicon has the same shape as a vidicon.)
