| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacitor microphone having a circuit for switching between external power supply and built-in power supply.SOLUTION: A capacitor microphone includes: a built-in power-supply circuit from a built-in power source to a microphone circuit; detection means for detecting the presence or absence of external power supply from an external power source to the microphone circuit; and switching means for blocking the power supply from the built-in power source when the detection means detects the external power supply. The detection means is configured by a light-emitting diode included in a photo-MOS relay and is connected in series between the external power source and the microphone circuit. The switching means is configured by a MOSFET included in the photo-MOS relay and is connected in series between the built-in power source and the microphone circuit. The MOSFET switches the connection between the built-in power-supply circuit and the microphone circuit by means of the blinking of the light-emitting diode. |
