supplement
The microphone is transmitted to the diaphragm of the microphone through the vibration of sound, which pushes the magnet inside to form a changing current, and the changing current is sent to the sound processing circuit behind for amplification. .
It is connected with a needle through a metal diaphragm, and the needle draws a pattern on the metal foil. When talking to the diaphragm, the air pressure difference makes the diaphragm move, thus making the needle move, and the movement of the needle is recorded on the metal foil. Subsequently, when the needle runs back on the metal foil, the vibration generated by scraping on the metal foil will make the diaphragm move and reproduce the sound. This purely mechanical system shows how much energy can be generated by vibration in the air.