Video Recording (Encyclopedia of Science)
Video recording is the process by which visual images are recorded on some form of magnetic recording device such as tape or a video disc. In magnetic recording, an unrecorded tape is wrapped around a rotating drum that carries the tape through a series of steps before it leaves as a recorded tape.
The actual recording of the tape occurs on a cylindrical device known as the head. The head consists of a coil of wire wrapped around a core made of ferrite (iron oxide). When a camera is focused on a scene, the visual images it receives are converted to an electrical signal within the camera. That electrical signal passes into the recording head.
When the electrical signal reaches the recording head, it passes through the wire coil. When an electrical current passes through a metal coil, it creates a magnetic field. The strength of the magnetic field (called a flux) created depends on the strength of the electric current passing through the coil of wire. The strength of the electric current, in turn, depends on the intensity of the light received by the video camera. If the camera sees a bright spot, it produces a strong electric current, and the strong electric current produces a strong magnetic flux. When the camera sees a dim spot, it produces a weak electric current, and that weak electric current produces a weak magnetic flux.
The strength of the...
(The entire section is 486 words.)
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