1857 On March 25th, Scott obtained the patent of acoustic vibration recorder. 1860 On April 9th, he recorded the song Auclairdelalune, which is the oldest sound known in human history.
The earliest tape recorder was called the phonograph, which was born in 1877. The man who invented the phonograph in the world is the world-famous inventor Thomas Alva Edison.
According to the phenomenon that the diaphragm in the telephone transmitter vibrates with the sound, Thomas Alva Edison made an experiment with a short needle, from which he got great inspiration. Speech speed can make the short needle vibrate accordingly. Then, in turn, this vibration will certainly make the original sound. So he began to study the problem of sound reproduction.
Extended data:
The recorder is mainly composed of built-in microphone, magnetic tape, recording and playback head, amplifier circuit, speaker and transmission mechanism.
When recording, the 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.
Playback is the reverse process of recording. When playing back, the tape passes through the gap near the playback head, and the changing magnetic field on the tape causes the coil of the playback head to generate induced current, which is the same as the recorded magnetic signal, so the coil generates current audio, which is amplified by the amplifier circuit and sent to the speaker, and the speaker restores the audio current to sound.
In the tape recorder, the recording and playback functions are completed by a single stupid head, and the magnetic head is connected to the little stupid bear when recording; When playing, the magnetic head is connected to the speaker.
References:
Baidu encyclopedia-tape recorder