Power circuit for condenser microphone

摘要

The present invention discloses a power circuit for a condenser microphone capable of automatically switching both internal power source and external power source without carrying out the switching operation of a switch. A positive side output line comprises a power switch for turning off the positive side output line to selectively connecting it to a ground side output line; a first diode connected with an input direction from the external power source being a forward direction between the power switch and an output terminal of the positive side output line; and a capacitor connected parallel with said power switch and said first diode so as to bypass them, a series circuit comprising the internal power source, a second diode and a load resistor with a direction from the ground side output line to the positive side output line being a forward direction being connected between a connection point of the power switch and the first diode and the ground side output line.