What is the construction and working principle of microphone?

Answer 1

Electric energy cause a membrane to move by turning into mechanical energy. The movement of the membrane causes the air pressure to besequentially increased and rarefied. This "train" of increased and rearefied air pressure propagates into the room, and if it strikes our ear drums we perceive it as sound.

Answer 2

1. When you speak, sound waves created by your voice carry energy toward the microphone. Remember that sound we can hear is energy carried by vibrations in the air.
2. Inside the microphone, the diaphragm (much smaller than you'd find in a loudspeaker and usually made of very thin plastic) moves back and forth when the sound waves hit it.
3. The coil, attached to the diaphragm, moves back and forth as well.
4. The permanent magnet produces a magnetic field that cuts through the coil. As the coil moves back and forth through the magnetic field, an electric current flows through it.
5. The electric current flows out from the microphone to an amplifier or sound recording device. Hey presto, you've converted your original sound into electricity! By using this current to drive sound recording equipment, you can effectively store the sound forever more. Or you could amplify (boost the size of) the current and then feed it into a loudspeaker, turning the electricity back into much louder sound. That's how PA (personal address) systems, Electric Guitar amplifiers, and rock concert amplifiers work.