Title:
CAPACITANCE MEASURING DEVICE
Document Type and Number:
Japanese Patent JP3025837
Kind Code:
B2
Abstract:
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).
Inventors:
Fusao Mori
Harumasa Machida
Harumasa Machida
Application Number:
JP30428095A
Publication Date:
March 27, 2000
Filing Date:
November 22, 1995
Export Citation:
Assignee:
Japan Aviation Electronics Industry Co., Ltd.
International Classes:
G01D3/028; G01D5/24; G01R27/26; G01F23/26; (IPC1-7): G01R27/26; G01D5/24; G01F23/26
Domestic Patent References:
| JP344568A | ||||
| JP217459A | ||||
| JP7198765A | ||||
| JP720172A |
Attorney, Agent or Firm:
Kusano Taku (1 person outside)