Accessories (II)

Tape recorder

A tape recorder is a machine that records sound or other electric signals such as video and digital magnetically on plastic tapes and plays them back after they are recorded. In an audio tape recorder, a microphone is used to pick up the sound and transform it into current. This current is fed to a transducer which is found in the tape recorder's recording head, which converts the current into corresponding magnetic flux variations that magnetize the fine particles of iron, cobalt, or chromium oxides on the tape as it passes by the head. During playback the tape passes over the playback head (often the same one used for recording) and the tape's magnetic field induces a current in the transducer. The current is then amplified and used to reproduce sound through a loudspeaker. Tape hiss, sound composed of high frequencies picked up at random during recording, is suppressed by several systems, among them Dolby, Dolby-B, Dolby-C, and dbx. Digital audio tape (DAT) and digital compact cassette (DCC) recorders transform audio signals into digital pulses, which are then stored on the tape. Both eliminate tape hiss and reproduce sound more accurately than analog recorders. Digital tape recording devices are also used to store programs and data for computers. See also videocassette recorder.