What is the recording and playback principle of tape recorder?

The recording principle of a tape recorder is that sound causes the microphone to generate an induced current that varies with the sound. The audio current enters the coil of the recording head after being amplified by the amplifier circuit, and a magnetic field varying with the audio current is generated at the gap of the magnetic head. The magnetic tape moves close to the gap of the magnetic head, the magnetic powder layer on the magnetic tape is magnetized, and the magnetic signal of sound is recorded on the magnetic tape.

The playback principle of the tape recorder is that when the tape passes through the slit of the playback head, the magnetic field generated by the "small magnet" on the tape passes through the coil of the playback head. Because the polarity and magnetic field strength of the "small magnet" are different, the magnetic flux it produces in the coil is constantly changing, so the induced current is generated in the coil, which can be amplified to make a sound in the speaker.

Extended data:

Magnetic tape is usually formed by plating a layer of granular magnetic material or evaporating a layer of magnetic oxide or alloy film on the plastic film tape base (bracket). Paper and celluloid are used as the belt base, but now polyester films with high strength, good stability and no deformation are mainly used.

Since 1956, American Ampex Company manufactured the video recorder, the video tape has gradually entered the fields of science and technology, culture and education, movies and family entertainment from TV broadcasting. In addition to chromium dioxide's cobalt-coated magnetic powder and metal magnetic powder, the Japanese also made miniature coated video tapes and developed barium ferrite vertical magnetization video tapes.

Baidu Encyclopedia-Tape

Baidu encyclopedia-recorder