5.5. Electrostatic microphone (capacitor microphone)
The electrostatic type of microphone is used extensively as a standard microphone for the measurement of sound pressure and as a studio microphone for the high-fidelity pickup of music. It can be made small in size so it does not disturb the sound field appreciably in the frequency region below 1000 Hz.
Sound-pressure levels as low as 10 dB and as high as 185 dB re 0.0002 μbar can be measured with standard instruments. The mechanical impedance of the diaphragm is that of a stiffness and is high enough so that measurement of sound pressures in cavities is possible. The electrical impedance is that of a pure capacitance.
The temperature coefficient for a well-designed ...