Crossword Dictionary
tape recorders
Tape recorder, recording system that makes use of electromagnetic phenomena to record and reproduce sound waves. The tape consists of a plastic backing coated with a thin layer of tiny particles of magnetic powder. The recording head of the tape deck consists of a tiny C-shaped magnet with its gap adjacent to the moving tape. The incoming sound wave, having been converted by a microphone into an electrical signal, produces a time-varying magnetic field in the gap of the magnet. As the tape moves past the recording head, the powder is magnetized in such a way that the tape carries a record of the electric signal. On playing back the tape past the recording head, the signal is reproduced and then converted through a loudspeaker into the original sound wave.
history
A number of experimental sound recording devices were designed and developed in the early 1900s in Europe and the United States. Recording and reproducing the sounds were two separate processes, but both were necessary in the development of the tape recorder. Up until the 1920s, especially in the United States, a type of tape recorder using steel tape was designed and produced. In 1928 a coated magnetic tape was invented in Germany. The German engineers refined the magnetic tape in the 1930s and 1940s, developing a recorder called the Magnetophon. This type of machine was introduced to the United States after World War II and contributed to the eventual widespread use of the tape recorder.