Cellulose acetate or Mylar ribbon {videotape} {audiotape} has an iron-oxide or cobalt-oxide coating. Ribbon passes over an electromagnet {magnetic head} {head, tape recorder}, of size 10^-3 square inches, at 1 7/8, 3 3/4, 7 1/2, or 15 inches per second. Recording head uses magnetic field to change coating magnetism pattern on tape {tape recorder}|. Tape magnetism pattern induces a magnetic field in receiving head, which makes an electric current. Demagnetizing heads use a random magnetic field to erase tape.
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7-Machine-Kinds-Electronic-Sound
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Date Modified: 2022.0224