JPS6461670A - Capacitance meter - Google Patents

Capacitance meter

Info

Publication number
JPS6461670A
JPS6461670A JP21846587A JP21846587A JPS6461670A JP S6461670 A JPS6461670 A JP S6461670A JP 21846587 A JP21846587 A JP 21846587A JP 21846587 A JP21846587 A JP 21846587A JP S6461670 A JPS6461670 A JP S6461670A
Authority
JP
Japan
Prior art keywords
output
switch
amplifier
voltage
integrator
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP21846587A
Other languages
Japanese (ja)
Inventor
Yoshiaki Kuraishi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP21846587A priority Critical patent/JPS6461670A/en
Publication of JPS6461670A publication Critical patent/JPS6461670A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G01R27/2605—Measuring capacitance

Abstract

PURPOSE:To measure a capacity value with a small error by inputting a known and an unknown capacity value to an integrator and forming a negative feedback circuit which inputs a trial capacity value obtained by using the output of a voltage-controlled oscillator controlled with the output of the integrator as a clock to the integrator. CONSTITUTION:The uninverted input of an operational amplifier 1 is grounded and an integrating capacitor 4 is placed between the input and output of the amplifier. The voltage-controlled oscillator 5 which is controlled with the output voltage of the amplifier 1, a reference voltage source VR which has a constant voltage to the ground, a switch S1 which selects the voltage source VR and the inverted input of the amplifier 1 alternately in synchronism with the variable clock of the oscillator 5, and a capacity 2 between the output of the switch and ground are arranged. A switch S2 which selects the ground and the inverted input of the amplifier 1 alternately in synchronism with a fixed clock and a capacitor 3 between the output of this switch S2 and the output of the switch S3 are arranged. A capacitor whose value is already known is used as one of the capacitors 2 and 3 and then the unknown capacity of the other is measured with a noise error which is smaller by one over the frequency of the oscillator 5.
JP21846587A 1987-09-01 1987-09-01 Capacitance meter Pending JPS6461670A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP21846587A JPS6461670A (en) 1987-09-01 1987-09-01 Capacitance meter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP21846587A JPS6461670A (en) 1987-09-01 1987-09-01 Capacitance meter

Publications (1)

Publication Number Publication Date
JPS6461670A true JPS6461670A (en) 1989-03-08

Family

ID=16720336

Family Applications (1)

Application Number Title Priority Date Filing Date
JP21846587A Pending JPS6461670A (en) 1987-09-01 1987-09-01 Capacitance meter

Country Status (1)

Country Link
JP (1) JPS6461670A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005517945A (en) * 2002-02-15 2005-06-16 ローズマウント インコーポレイテッド Bridge capacitor sensor measurement circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005517945A (en) * 2002-02-15 2005-06-16 ローズマウント インコーポレイテッド Bridge capacitor sensor measurement circuit

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