| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacitor microphone including a proximity sensor comprising an infrared ray emitting diode and an infrared ray receiving device that prevents production of noise and malfunction of the infrared ray receiving device in lighting the infrared ray emitting diode by an AC power supply. SOLUTION: The capacitor microphone operated by a prescribed DC power supply wherein an oscillation circuit 22 lights up the infrared ray emitting diode 20 by an AC power supply with a prescribed frequency and a microphone output is turned ON/OFF by an output signal from the infrared ray receiving device 21 tuned to the frequency, is provided with two DC-DC converters 23, 24 connected in parallel with the DC power supply, and the one DC-DC converter 23 supplies power to the infrared ray emitting diode 20 and the oscillation circuit 22, and the other DC-DC converter 24 supplies power to the infrared ray receiving device 21. COPYRIGHT: (C)2006,JPO&NCIPI |
