CAPACITANCE MEASURING DEVICE

摘要

PROBLEM TO BE SOLVED: To increase accuracy by correcting an error caused by a measurement cable. SOLUTION: The output of a measurement signal generator 2 is supplied to the close terminal of a cable 3 where one terminal of a capacitance 4 to be measured is connected to a remote terminal via a resistor 21, a signal of a close terminal of a cable 5 where the other terminal of the capacitance 4 is connected to a remote terminal is inputted to a capacity/voltage conversion circuit 12 and is converted to a voltage corresponding to a capacitance Cx of a sample, and then the signal is inputted to a capacity operation means 13 to calculate an approximate value Cx' of a measurement capacity. A voltage Vr=rI0 between the terminals of the resistor 21 is measured by a differential voltage measurement circuit 22 and is inputted to a cable length operation means 23, thus calculating a cable length L. A means 24 for calculating the amount of correction calculates an amount of correction ΔC from the cable length L and the approximate measurement value Cx' and a correction means 25 performs correction operation (Cx≈Cx'+ΔC).