| 摘要 |
The present invention provides a condenser microphone having a proximity sensor consisting of an infrared light emitting diode and an infrared photodetector, the condenser microphone preventing the occurrence of noise and the malfunctioning of the infrared photodetector when the infrared light emitting diode is lighted using an AC component. Specifically, the present invention provides a condenser microphone operated using a predetermined DC power source; an infrared light emitting diode 20 is lighted at a predetermined frequency by an oscillation circuit 22 using an AC component, and a microphone output is turned on and off by an output signal from the infrared photodetector 21 which is tuned to the predetermined frequency. The condenser microphone further includes two DC-DC converters 23 and 24 connected in parallel with the DC power source. One 23 of the DC-DC converters 23 supplies power to the infrared light emitting diode 20 and the oscillation circuit 22. The other DC-DC converter 24 supplies power to the infrared photodetector 21.
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