JPS5514732A - Variable resistance device - Google Patents

Variable resistance device

Info

Publication number
JPS5514732A
JPS5514732A JP8729078A JP8729078A JPS5514732A JP S5514732 A JPS5514732 A JP S5514732A JP 8729078 A JP8729078 A JP 8729078A JP 8729078 A JP8729078 A JP 8729078A JP S5514732 A JPS5514732 A JP S5514732A
Authority
JP
Japan
Prior art keywords
amplifier
resistance
fet1
fet
source
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
JP8729078A
Other languages
Japanese (ja)
Inventor
Yoji Yamamoto
Tatsuo Matsumoto
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 JP8729078A priority Critical patent/JPS5514732A/en
Publication of JPS5514732A publication Critical patent/JPS5514732A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/24—Frequency-independent attenuators
    • H03H11/245—Frequency-independent attenuators using field-effect transistor

Landscapes

  • Networks Using Active Elements (AREA)

Abstract

PURPOSE:To secure an electric control in terms of the exponent function for the resistance value to the control input as well as to eliminate the fluctuation due to the temperature to keep a high stability. CONSTITUTION:The output of arithmetic amplifier 2 is applied to the gate of FET1 corresponding to the variable resistance element, and the DC is applied between the source and the drain from constnt current source I0. Then the source is grounded, and the drain is connected to the negative inverse input terminal of amplifier 2 via resistance Rf as well as to output terminal 3 via capacity C0. Control voltage VIN suplied from terminal 4 is converted into the exponent function type through transistors Q1 and Q2 having the common emitter to be then supplied to amplifier 2, and this output controls FET1. The product of the DC constant current supplied to FET and the resistance value of FET is fed negatively back to amplifier 2. As a result, FET1 varies the resistance in terms of the exponent function to the control input voltage. At the same time, the temperature compensation is given to resistance RT of the input side to secure constant q/kT.(RT/RI + RT), where q is the electron charge and k is the Boltzmanns constant. Thus both the nonlinearity of FET and the temperature fluctuation can be ignored.
JP8729078A 1978-07-18 1978-07-18 Variable resistance device Pending JPS5514732A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8729078A JPS5514732A (en) 1978-07-18 1978-07-18 Variable resistance device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8729078A JPS5514732A (en) 1978-07-18 1978-07-18 Variable resistance device

Publications (1)

Publication Number Publication Date
JPS5514732A true JPS5514732A (en) 1980-02-01

Family

ID=13910664

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8729078A Pending JPS5514732A (en) 1978-07-18 1978-07-18 Variable resistance device

Country Status (1)

Country Link
JP (1) JPS5514732A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6243911A (en) * 1985-08-22 1987-02-25 Fujitsu Denso Ltd Ac current control system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6243911A (en) * 1985-08-22 1987-02-25 Fujitsu Denso Ltd Ac current control system

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