| 摘要 |
PURPOSE:To eliminate fluctuations in power supply voltage and protect the input of an electronic component by connecting one side of a series circuit of a Zener diode and a diode to the input side of the electronic component and the other side to the ground. CONSTITUTION:One side of a series circuit of a Zener diode 8 and a diode 9 is connected to the input side of an electronic component 4 such as A/D converter or the like, and the other side is connected to ground G of power supplies 1 and 2. If, for instance, the output of an amplifier 5 is saturated at a negative side, not only an input protection diode 7 of electronic component 4 but also a circuit of the Zener diode 8 and the diode 9 connected between the input of the electronic component 4 and a common ground terminal of a first power supply 1 begin to operate and a current flowing from a second power supply 2 to the amplifier 5 is eliminated by applying a current from the ground of the power supply having a larger capacity to the amplifier 5. By doing this, the fluctuations in the power supply voltage V4 can be eliminated and the input of the electric component 4 can be protected. |
