| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive circuit for an electret condenser microphone that can realize low power consumption. SOLUTION: The drive circuit 20A for the electret condenser microphone 10 having a capacitor whose capacitance changes with vibration of a vibration membrane and a FET whose gate is connected to a 1st electrode of the capacitor and whose source is connected to a 2nd electrode of the capacitor and a reference level, is provided with a drain resistor R21 that is connected between a power supply voltage supply line and the drain of the FET, a switch 22 that switches electrical connection state/electrical disconnection state of a power supply line to/from the drain D of the FET according to a timing pulse, and a timing generating circuit 23 that generates the timing pulse to switch the connection state/disconnection state of the switch 22.
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