Microphone also called by names like mic or mike, is a transducer that converts sound into electric signal. Microphones are used in all the devices that needs human interaction through voice. Any voice recorder, voice commands to your computer or mobile phone, telephone, all require microphone for their purpose. Microphones have always became better and better through advancement of technology.
Based on the type of method a microphone converts sound into electric signal, microphones are mainly of following types –
- Dynamic microphone
- Condenser microphone
- Piezoelectric microphone
This type of microphone uses an induction coil to convert sound into electrical signal. The moving induction coil is suspended in a permanent magnetic field and is attached to a diaphragm (thin membrane). When a sound wave hits the diaphragm, diaphragm starts vibrating and moves induction coil, the movement of the induction coil in the magnetic field produces an electric current. Hence, a sound wave is converted into an electric signal.
This microphone uses a capacitor in place of a moving induction coil and diameter. A capacitor stores charge in the form of electrostatic charge. The distance between the two plates of a capacitor determines the amount of charge it can hold. The front plate of the capacitor acts as a diaphragm. When a sound wave hits the front plate, the distance between two capacitor plates changes. This change in the capacitance of a capacitor produces a change ij electric current and thus, an electric signal is produces in relation to the sound waves.
Piezoelectric substances are the substances that produce electric current when a pressure is applied on them. Thus, the pressure created by the sound waves on the piezoelectric substance produces an electric current. This way a piezoelectric microphone converts a sound signal into an electric signal.
Based on the direction of operation of microphone, it is of following types
These type of microphones record sound only from front direction. They are used when only the sound from front side is to be recorded, eliminating the other sounds coming from different directions other than the front direction.
These type of microphones record sound from front and backside. Sounds from sides other than the front and the back are eliminated. They are used when two person sitting opposite to each other to record their sound.
These type of microphones record sound from all the directions. They are used when many sounds are to be recorded at the same time, like sounds from different music instruments at the same time.
Microphone array means any number of microphones operating together. It is usually a combination of many omnidirectional microphones or the combination of different types of microphones like omnidirectional, unidirectional, bidirectional microphones. Microphone arrays have many applications like high fidelity sound recording, finding location with sound, environmental noise monitoring, technology for recording realistic sound and many other applications where high quality of sound us required.
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