| 摘要 |
An electret condenser microphone of small power consumption and capable of rejecting noise over a broad band, the electret condenser microphone being suitable for use as e.g. a microphone in a mobile telephone or a sensor disposed inside an engine room of an automobile. The microphone includes an electro-acoustic transducer (M) having an electret portion (E) provided at least one of a diaphragm (6) acting as an electrode and a stationary electrode (2, 25) disposed in opposition to the diaphragm (6), and an FET (10) effecting an impedance conversion on an output from the electro-acoustic transducer (M) and then outputting the converted output. The FET (10) is of MOS type. Further, a capacitor (11) and a varistor (12) are provided in parallel between the signal line (L) of the FET (10) and the ground (18) and a resistor (13) is incorporated in series in the signal line (L). <IMAGE>
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