Patent ID: 8498431

Claim:
A capacitor microphone comprising: a capacitor microphone unit including a diaphragm that vibrates upon receiving sound waves and a fixed electrode arranged opposite to the diaphragm with a space therebetween; and a polarization voltage generating circuit that generates polarization voltage to be applied across the diaphragm and the fixed electrode, wherein the polarization voltage generating circuit includes: an oscillating circuit that alternately turns on and off DC power, coils that are electromagnetically coupled to each other to boost a voltage of a power alternately turned on and off, and a DC boosting circuit including a rectifying circuit that rectifies a boosted voltage, and the coils are formed of two inductors that are electromagnetically coupled and are provided with an electromagnetic coupling adjusting unit with which a level of electromagnetic coupling between the two inductors is adjusted to adjust the polarization voltage, wherein the electromagnetic coupling adjusting unit is formed of a magnetic material provided across the two inductors and the level of electromagnetic coupling between the two inductors is adjusted by adjusting the position of the magnetic material with respect to the two inductors.