JPS5619408A - Detecting circuit for electrostatic capacity difference of differential capacitor - Google Patents

Detecting circuit for electrostatic capacity difference of differential capacitor

Info

Publication number
JPS5619408A
JPS5619408A JP9572479A JP9572479A JPS5619408A JP S5619408 A JPS5619408 A JP S5619408A JP 9572479 A JP9572479 A JP 9572479A JP 9572479 A JP9572479 A JP 9572479A JP S5619408 A JPS5619408 A JP S5619408A
Authority
JP
Japan
Prior art keywords
constant
operational amplifier
electrostatic capacity
differential capacitors
output voltage
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.)
Granted
Application number
JP9572479A
Other languages
Japanese (ja)
Other versions
JPS5927844B2 (en
Inventor
Hiroaki Saijo
Eiji Okamura
Susumu Omori
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.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
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 Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP54095724A priority Critical patent/JPS5927844B2/en
Publication of JPS5619408A publication Critical patent/JPS5619408A/en
Publication of JPS5927844B2 publication Critical patent/JPS5927844B2/en
Expired legal-status Critical Current

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  • Transmission And Conversion Of Sensor Element Output (AREA)
  • Measurement Of Resistance Or Impedance (AREA)

Abstract

PURPOSE: To lessen an influence of variation in electrostatic capacity due to fluctuations of temperature, etc., by constituting differential capacitors as part of the time- constant part of a sending circuit.
CONSTITUTION: The output voltage of the 2nd operational amplifier A2 is applied to the common connection part of differential capacitors C1 and C2 by way of resistance R2. Further, the common connection part, connected to one terminal of operational amplifier A2, operates as an oscillating circuit. Time constant T of the oscillating circuit including operational amplifier A2 is (C1+C2)R2. Output voltage e0 of operational amplifier A1 is expressed by formula I. Namely, resistances R1 and R2 are constant and electric power voltage E0 is fixed by constant-voltage diodes D5 and D6. Since C1 and C2 are differential capacitors, C1+C2 is invariably constant and output voltage e0 is in proportion to C1-C2. Therefore, even when capacities of differential capacitors vary with temperature, their influences can remarkably be reduced.
COPYRIGHT: (C)1981,JPO&Japio
JP54095724A 1979-07-27 1979-07-27 Differential capacitance difference detection circuit Expired JPS5927844B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP54095724A JPS5927844B2 (en) 1979-07-27 1979-07-27 Differential capacitance difference detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP54095724A JPS5927844B2 (en) 1979-07-27 1979-07-27 Differential capacitance difference detection circuit

Publications (2)

Publication Number Publication Date
JPS5619408A true JPS5619408A (en) 1981-02-24
JPS5927844B2 JPS5927844B2 (en) 1984-07-09

Family

ID=14145413

Family Applications (1)

Application Number Title Priority Date Filing Date
JP54095724A Expired JPS5927844B2 (en) 1979-07-27 1979-07-27 Differential capacitance difference detection circuit

Country Status (1)

Country Link
JP (1) JPS5927844B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4418631B4 (en) * 1993-05-28 2005-04-14 General Scanning Inc., Watertown Capacitive transducer with feedback control

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4418631B4 (en) * 1993-05-28 2005-04-14 General Scanning Inc., Watertown Capacitive transducer with feedback control

Also Published As

Publication number Publication date
JPS5927844B2 (en) 1984-07-09

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