| 摘要 |
PURPOSE:To obtain a capacity-type convertor of high accuracy by changing charging and discharging currents to a variable capacity at constant or arbitrary frequency and calculating for correction a through-rate portion of an operational amplifier. CONSTITUTION:A variable capacity C1 changing its capacity corresponding to a physical quantity subject to detection, an operational amplifier Q1 connected with an end of this capacity on the non-inversion input end and applied with a divided voltage of an output end voltage and a constant voltage on the inversion input end and an invertor G1 are installed and by a voltage dividing point of an output of the convertor Q1 and an output of the invertor G1, the constant current value admitted to the non-inversion input end of the amplifier Q1 is switched with a switched and correction is conducted by calculating a through- rate of the operational amplifier. By this arrangement, as a though-rate of the operational amplifier can be measured by a micro-computer, by making corrective calculation relative to an output of the invertor based upon these results of measurements, an electric signal corresponding accurately to a physical quantity can be issued out.
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