| 摘要 |
PURPOSE:To obtain a capacity converter that is hardly affected by the scattering of electrons or a temperature by comparing the output of operation amplifying means and an operating voltage with each other to output a binary voltage and applying the voltage related to the binary voltage to a first input end. CONSTITUTION:The inverted input end (-) of a differential amplifier Q1 is connected to one end of a sensor capacity CM via a cable CB wherein a conductor CW is surrounded by a guard GD. The inverted input end (-) of a comparator Q2 is connected to the output end of the amplifier Q1 and an operating voltage V0 is applied to the non-inverted input end (+) of the comparator Q2 via a resistor R1. Switches S1 and S2 are connected between the positive power supply +E of the amplifier Q1 and a positive power supply end T1 and between the negative power supply -E and a negative power supply end T2, respectively. The closing and opening of the switches S1 and S2 are controlled by the output of the comparator Q2. A binary operating voltage V0 to which the output of a comparator Q3 is suitably divided is obtained at the output end of an amplifier Q4. Thus, a capacity converter that is hardly affected by the scattering of electrons of a temperature can be obtained.
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