|MadSci Network: Engineering|
A VCR uses a cartridge containing tape. When you insert the catridge, the VCR grabs the tape and wraps it around the read head. The tape is positioned at an angle to the head so that as the head spins it sweeps across the tape at an angle somewhere between the horizontal flow of the tape and a vertical line from the bottom edge of the tape to the top of the tape. This approach lets the head use nearly the entire surface of the tape and lets the read portion of the head move at a greater speed across the tape than the speed of the tape itself would cause. When you pause the VCR and look at frozen video, the tape is not moving and the head is sweeping across on portion of the tape over and over. The same principles apply to recording video to the tape.
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