| 摘要 |
PURPOSE:To provide an amplifier for condenser microphone which difficultly receives the influence of a noise such as due to ripples of a power source driving and simultaneously has a function to invert a phase simultaneously. CONSTITUTION:A buffer amplifier circuit 11 of source-grounded type is equipped with a microphone capsule 1, a diode 2, and a FET 3, and the drain of the FET 3 that is the output terminal of the circuit is connected to the input terminal of a current mirror 12. The output terminal of the current mirror 12 is connected to a load resistor 13 whose one terminal is grounded. The voltages on both terminals of the resistor go to the output of the amplifier 101, and they are inputted to a loudspeaker amplifier 110. |
