It was developed in Germany, based on magnetic wire recording. Magnetic tape is a medium for magnetic recording, made of a thin, magnetizable coating on a long, narrow strip of plastic film. Although digitization of materials on fragile magnetic media in library and information science is a common practice, there remains a need for conserving the actual physical magnetic tape and playback equipment as artifacts. Multiple types of magnetic media exist but are mainly in the form of open reels or enclosed cassettes. Preservation of magnetic audiotape comprises techniques for handling, cleaning and storage of magnetic audiotapes in an archival repository. Magnetic recording techniques are used in the hard disc drives in computers and the floppy discs but not in CDs where a laser is used. The signals may be recorded as either digital or analogue. This is done to make sure that none of the previous recording is left on the tape. This signal jumbles up the tiny iron oxide grains before a new recording takes place. This is fed by a high frequency signal (60 kHz) which is well about the range of human hearing. The tape recorder also has an erase head. A changing magnetic field on the tape is converted to a voltage by the playback head, this is amplified by the amplifier and then fed to a loudspeaker. The reverse happens at the playback stage. The recording head should be as close to the tape as possible so that the changing magnetic field can affect the iron oxide grains more easily. Slow tape speed compresses the information into a small length and a poorer recording results. The faster the tape moves the better the recording because the information (lets say the music) is spread out over a longer piece of tape. (d) this changing magnetic field arranges the grains of iron oxide on the tape into a pattern that 'mirrors' the changing sound received by the microphone.

(a) the microphone picks up the sound wave and converts it to a small changing voltage When you record data, lets say some music, on the tape the following things happen: Warning вЂ“ don't try to do this with a tape that already has some music or data stored on it вЂ“ you will ruin it!Д®ach grain of iron oxide acts like a tiny magnet and on a tape that has no data stored on it these gains are arranged irregularly on the tape вЂ“ the tape is unmagnetised. You can tell that the tape is magnetic by attracting it with a magnet. Tape recorders store the information music, speech or data, on plastic tape that is coated with iron oxide powder. Although tape recorders have been replaced in everyday use by Cd players and devices such as iPods they still provide a really useful way to understand the ideas of electromagnetic induction.

Nms magnetic resonator