| 摘要 |
PURPOSE:To reduce noise without necessitating a resistor, by applying an input signal on an input stage on one side, connecting a hold capacitor between an input and an output on the other side, and performing the connection and disconnection of one end of the hold capacitor to a common potential point synchronizing with the switching of those two input stages. CONSTITUTION:An amplifier 30 which selects either one of the two input stages by preparing the two input stages and switching an operating current to be supplied to those input stages is used, and the hold capacitor 32 is connected between the input stage on one side and the output of the amplifier 30. Also, a FET31 as a switch whose ON/OFF is controlled interlocking with the switching of the operating current is connected between the side of the hold capacitor 32 not being connected to the output of the amplifier 30 and the common potential point. Thus, the input signal to be held is applied on the input stage on the other side of the amplifier 30. In such a way, it is possible to reduce the noise and to obtain high accuracy without necessitating the resistor.
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