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  • A camera tube in which the light from a scene is focused upon a photocathode from which electrons are ejected with an intensity proportional to the intensity of the light in the various locations of said scene. These electrons are focused upon a target, which produces secondary emissions of electrons, in a manner proportional to the electron density of the photocathode, forming an electronic image. The opposite side of this target is scanned by an electron beam, and its interaction with the target forms an intensity-modulated beam which is then multiplied to produce the video output. Utilized in TV broadcasting.