| 摘要 |
<p>An impedance converter for capacitor microphone in which a surge voltage of electrostatic discharge, or the like, is not applied directly to a capacitor and even a capacitor having a low withstand voltage can endure against the surge voltage while reducing the size. The impedance converter (1) reduces the output impedance concerning to the electric signal of a capacitor microphone (9) and comprises a source follower circuit (5) employing a field effect transistor (FET) 2. The source follower circuit (5) has a power supply line (6) and an output signal line (7) connected in series with resistors R1 and R2, respectively, and capacitors C1 and C2 are connected between a ground line (8)and the power supply line (6) and the output signal line (7), respectively, on the source follower circuit (5) side of the resistors R1 and R2.</p> |
