JPS5514732A - Variable resistance device - Google Patents
Variable resistance deviceInfo
- 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
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.
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)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6243911A (en) * | 1985-08-22 | 1987-02-25 | Fujitsu Denso Ltd | Ac current control system |
-
1978
- 1978-07-18 JP JP8729078A patent/JPS5514732A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6243911A (en) * | 1985-08-22 | 1987-02-25 | Fujitsu Denso Ltd | Ac current control system |
JPH0570969B2 (en) * | 1985-08-22 | 1993-10-06 | Fujitsu Denso |
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