JPH02105115U

JPH02105115U -

Info

Publication number: JPH02105115U
Application number: JP1288989U
Authority: JP
Priority date: 1989-02-06
Filing date: 1989-02-06
Publication date: 1990-08-21

Description

[Brief explanation of drawings]

第１図及び第３図は本考案のそれぞれ異なる実
施例の構成図、第２図は第１図及び第３図におけ
る同じ要部の構成図である。１１，１９……差圧変換器、１４……充電回路
、１５……第１放電回路、１６……第２放電回路
、１７……計測信号出力部、１８……電源部、２
０……信号変換部、Ｃ_１……第１静電容量、Ｃ_２……第２静電容量、Ｃｓ……浮遊容量、Ｉ_１ｃ…
…第１充電電流、Ｉ_２ｃ……第２充電電流、Ｉ_１
ｄ……第１放電電流、Ｉ_２ｄ……第２放電電流、
Ｉ_３……直線性誤差補正電流、Ｉ_０……計測信号
、Ｔ_０１，Ｔ_０２，Ｔ_１１，Ｔ_１２，Ｔ_２１，Ｔ
_２２……ＦＥＴ。 1 and 3 are configuration diagrams of different embodiments of the present invention, and FIG. 2 is a configuration diagram of the same essential parts as in FIGS. 1 and 3. 11, 19...differential pressure converter, 14...charging circuit, 15...first discharge circuit, 16...second discharge circuit, 17...measurement signal output section, 18...power supply section, 2
0...Signal converter, _C1 ...First capacitance, _C2 ... Second capacitance, Cs ... Stray capacitance, I _1c ...
...First charging current, I _2c ...Second charging current, I _{1
d} ...first discharge current, _I2d ...second discharge current,
I ₃ ... Linearity error correction current, I ₀ ... Measurement signal, T ₀₁ , T ₀₂ , T ₁₁ , T ₁₂ , T ₂₁ , T
₂₂ ...FET.

Claims

[Claims for Utility Model Registration] (1) First and second capacitances whose respective capacitance values vary differentially depending on the measured quantity, the first charging current, the second charging current, and linearity. The first capacitance is charged with the first charging current while controlling the sum with the error correction current to be constant, and the second capacitance is charged with the second charging current, and the linearity is a charging circuit that outputs an error correction current; and first and second capacitances corresponding to the first and second capacitances that simultaneously discharge all charges of both capacitances charged with the charging currents. a discharge circuit; a measurement signal output unit that outputs a measurement signal according to a difference between a first discharge current flowing through the first discharge circuit; and a second discharge current flowing through the second discharge circuit; A measured quantity converter that converts the measured quantity into the measured signal, comprising a power supply section that alternately and continuously drives the discharge circuit, and is based on the stray capacitance associated with each of the two capacitances. A linearity error between the measured quantity and the measurement signal is corrected by the linearity error correction current, and at least some of the active elements in each of the charging circuit and the measurement signal output section are junction type FETs. A measured quantity converter characterized by: (2) comprising: both impedance elements whose respective impedance values differentially change according to the measured quantity; and a signal conversion section which outputs a measurement signal proportional to the difference between the respective impedance values of the impedance elements; A measured quantity converter for converting a measured quantity into the measurement signal, characterized in that at least a part of the active elements in the signal conversion section are junction type FETs.