| 摘要 |
PURPOSE:To increase an output when an AC power supply is used more than that when a DC power supply is used, by connecting an amplifier circuit for exclusive use of the AC power supply further, to a post-stage of the amplifier circuit operated at both AC and DC power. CONSTITUTION:When a common terminal (c) of changeover switches 4, 8 is selected to a fixed terminal (a), a voltage V3 of a DC power supply 7 is applied to the 1st amplifier circuit 2. Then, an output of the amplifier circuit 2 is applied to a load 5 directly via the changeover switch 4. When the common terminal (c) of the changeover switches 4, 8 is selected to the other fixed terminal (b), one output V1 of an AC power supply circuit 6 is applied to the amplifier circuit 2, and the other output V2 is applied to an amplifier circuit 3 for exclusive use of the AC power supply. The output of the amplifier circuit 2 is amplified further at the amplifier circuit 3 and applied to the load 5 via the changeover switch 4. Thus, in this case, a larger output than that at the use of the DC power supply 7 is obtained. |
