The microphone works 浏覽 887 次 發布時間:2014-9-15 | ||
Microphone is by the vibration of the sound to the diaphragm of the microphone, push the magnets inside the form change of current, this change of current treatment of amplification circuit to the back of the voice. Sound is a wonderful thing. We hear different voices, are produced by our tiny differential pressure of the surrounding air. Amazing is that the air will these differential pressure so intact, so true to transport a long distance. It is made of metal diaphragm is connected to the needle, the needle scratch pattern on a piece of metal foil. When you toward the diaphragm's speech, the air pressure errand diaphragm movement, so that the needle movement, the movement of the needle is recorded on the metal foil. Back then, when you are on the metal foil to run the needle, the vibration of the scratches on the metal foil can make the diaphragm movement, the voice again. The purely mechanical system shows the vibration can produce how much energy in the air! All modern microphone and microphone first needs to be done are no different. Is only in the form of electricity, instead of a mechanical way. The microphone will change in the air pressure wave changes into electrical signals. There are five common technique used to complete the conversion. carbon The oldest and most simple microphone, use carbon dust. In the history of the first phone using this technology, now still in use in some of the telephone. In the side of the carbon dust has a very thin metal or plastic diaphragm. When sound waves hit the diaphragm, they compressed carbon dust, change resistance. By giving carbon electricity, changed the resistance will change the current size. For more information, please see the working principle of the telephone. dynamic Dynamic microphone using electromagnetic effect. When the magnet (or coil) through the wire, magnet induced in the wire and the electric current. In dynamic microphone when sound waves hit the diaphragm, diaphragm moving magnet, this movement is small current. ribbon In the ribbon microphone, a thin ribbons hanging in magnetic field. Sound waves move the band, so as to change the electric current flowing through it. capacitor Condenser microphone is actually a capacitor, one of the capacitor is extremely movement in response to the sound waves. Movement changed the capacitance of capacitor, these changes be amplified, resulting in a signal can be measured. Condenser microphones are usually use a small battery, provide capacitor voltage. crystal Some crystal shape will change their electrical properties (for an example of this phenomenon, please see the working principle of the quartz watch). Through the diaphragm is connected to the crystal, when sound waves hit the diaphragm, crystal will produce signals. |