JPH0216450B2 - - Google Patents
Info
- Publication number
- JPH0216450B2 JPH0216450B2 JP56025752A JP2575281A JPH0216450B2 JP H0216450 B2 JPH0216450 B2 JP H0216450B2 JP 56025752 A JP56025752 A JP 56025752A JP 2575281 A JP2575281 A JP 2575281A JP H0216450 B2 JPH0216450 B2 JP H0216450B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- output
- pulse width
- capacitor
- coefficient
- 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.)
- Expired - Lifetime
Links
- 239000003990 capacitor Substances 0.000 claims description 25
- 238000010586 diagram Methods 0.000 description 10
- 238000006073 displacement reaction Methods 0.000 description 8
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/24—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
- G01D5/241—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes
- G01D5/2417—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes by varying separation
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Description
【発明の詳細な説明】
本発明は、圧力、差圧等の被測定量に応じて可
動電極が変位し容量が変化する可変コンデンサを
用いた容量式変換器に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capacitive transducer using a variable capacitor whose movable electrode is displaced and whose capacitance changes depending on a measured quantity such as pressure or differential pressure.
一般に容量式変換器においては、可変コンデン
サに並列に存在するストレイ容量の影響を受けて
直線性が悪い欠点があつた。また圧力変換器や差
圧変換器のように被測定量を金属ダイヤフラムで
変位に換えて可変コンデンサの容量を変化させる
場合には、金属ダイヤフラムの変位量が大きくな
ると被測定量に比例しなくなるため、被測定量と
出力とが非直線的になる欠点があつた。 In general, capacitive converters have the disadvantage of poor linearity due to the influence of stray capacitance existing in parallel with the variable capacitor. Also, when changing the capacitance of a variable capacitor by converting the measured quantity into displacement using a metal diaphragm, such as in a pressure transducer or differential pressure transducer, if the displacement of the metal diaphragm becomes large, it will no longer be proportional to the measured quantity. However, there was a drawback that the amount to be measured and the output were non-linear.
本発明は、上述の如き非直線性を有効に補償で
きる容量式変換器を実現したものである。 The present invention realizes a capacitive converter that can effectively compensate for the nonlinearity described above.
第１図は本発明変換器一実施例を示す接続図で
ある。図において、C1は可変コンデンサで、圧
力等の被測定量に応じて変位する可動電極１０と
この可動電極１０に対向配置されている固定電極
１１とで構成されており、可動電極１０は基準点
に、固定電極１１はスイツチSW1に接続されてい
る。C2は固定コンデンサで、一方の電極はスイ
ツチSW2に、他方の電極は基準点に接続されてい
る。SW1のON側とSW2のOFF側とがP1点で共通
に接続され、SW1のOFF側とSW2のON側とがP2
点で共通に接続されている。BAは演算増幅器
OPを用いたバツフア増幅器で、OPの非反転入力
端子(+)に共通接続点P1が接続され、OPの出力
端子が前記共通接続点P2に接続されるとともに
非反転入力端子(-)に接続されて、P2の電位E2を
P1の電位E1に常に等しく保つ。COは比較器で、
ブロツク図内に示す如くヒステリシス特性を持つ
ており、前記共通接続点P1の電位E1が上限域値
Ｈを越えたときオンからオフに反転し、E1が下
限域値Ｌに達するとオンに復する一定振幅Erの
パルス幅電圧をPWを発生する。このパルス幅電
圧PWは抵抗Ｒを介して共通接続点P1に与えられ
るとともに、前記スイツチSW1，SW2を駆動し
て、コンデンサC1の充電とコンデンサC2の放電
を制御する。またパルス幅電圧PWはスイツチ
SW３を駆動し、PWがオンのとき負の基準電圧
−Es2をフイルタ回路FCに与え、オフのとき正の
基準電圧Es1と出力電圧Eoに関連した帰還電圧
kEoとの和をフイルタ回路FCに与える。すなわ
ちスイツチSW3のON側には負の基準電圧Es2が
加えられており、OFF側には正の基準電圧Es1と
出力電圧Eoを係数器Ｋでｋ倍した帰還電圧kEo
とが加算器ADで加算された後加えられている。
AMPは一定ゲインA1の増幅器で、フイルタ回路
FCで平滑された電圧を増幅し出力電圧Eoとして
出力端子OUTに与えるものである。 FIG. 1 is a connection diagram showing an embodiment of the converter of the present invention. In the figure, C 1 is a variable capacitor, which is composed of a movable electrode 10 that is displaced according to a measured quantity such as pressure, and a fixed electrode 11 that is disposed opposite to this movable electrode 10. At this point, the fixed electrode 11 is connected to the switch SW1 . C 2 is a fixed capacitor, one electrode is connected to the switch SW 2 and the other electrode is connected to the reference point. The ON side of SW 1 and the OFF side of SW 2 are commonly connected at P 1 point, and the OFF side of SW 1 and the ON side of SW 2 are connected at P 2.
connected in common at points. BA is operational amplifier
In a buffer amplifier using an OP, a common connection point P1 is connected to the non-inverting input terminal (+) of the OP, and a common connection point P1 is connected to the common connection point P2 , and the non-inverting input terminal (-) is connected to the output terminal of the OP. connected to the potential E 2 of P 2
The potential of P 1 is always kept equal to E 1 . CO is a comparator,
As shown in the block diagram, it has a hysteresis characteristic, and it switches from on to off when the potential E1 at the common connection point P1 exceeds the upper limit value H, and turns on when E1 reaches the lower limit value L. A pulse width voltage with a constant amplitude Er that returns to PW is generated. This pulse width voltage PW is applied to the common connection point P1 via the resistor R, and drives the switches SW1 and SW2 to control charging of the capacitor C1 and discharging of the capacitor C2 . In addition, the pulse width voltage PW is
Drives SW3 to provide a negative reference voltage -Es 2 to the filter circuit FC when PW is on, and a positive reference voltage Es 1 and a feedback voltage related to the output voltage Eo when it is off.
The sum with kEo is given to the filter circuit FC. In other words, a negative reference voltage Es 2 is applied to the ON side of the switch SW 3 , and a positive reference voltage Es 1 and a feedback voltage kEo obtained by multiplying the output voltage Eo by k using a coefficient multiplier K are applied to the OFF side.
are added after being added by adder AD.
AMP is an amplifier with a constant gain of A 1 , which is a filter circuit.
The voltage smoothed by the FC is amplified and applied to the output terminal OUT as the output voltage Eo.
このように構成した本発明において、比較器
COの出力PWがオンであると、SW1，SW2がON
側になりコンデンサC1が抵抗Ｒを介して充電さ
れ、充電電圧Ec1はC1Rの時定数で上昇する。こ
の電圧Ec1が比較器COの入力電圧E1となつてい
るので、Ec1が大きくなりCOの上限域値Ｈを越え
ると、COの出力PWはオフになる。COの出力
PWがオンの間コンデンサC2の端子電圧Ec2はOP
によつてEc1を追従し、常にEc2＝Ec1を保つてい
る。COの出力PWがオフになり、SW1，SW2が
OFF側に接続されると、コンデンサC2の電荷が
抵抗Ｒを介して放電され、C2の電圧Ec2はC2Rの
時定数で減少する。このEc2がCOの入力電圧E1
となつているので、Ec2が減少し下限域値Ｌに達
すると、COの出力PWはオンに復する。COの出
力PWがオフの間コンデンサC1の端子電圧Ec1は
OPによつて追従し、常にEc1＝Ec2を保つてい
る。このようにして比較器COとスイツチSW1，
SW2および一対のコンデンサC1，C2からなるル
ープは周期的にオンオフを繰り返し自励振動す
る。これらの関係を示したのが第２図の波形図
で、イは比較器COの入力電圧E1の波形図、ロは
比較器出力PWの波形図、ハはスイツチSW1，
SW2の動作波形図ある。自励振動ループがオンと
なつている時間t1はC1Rに、オフとなつている時
間t2はC2Rにそれぞれ比例する。したがつて、自
励振動ループのパルス幅信号PWのデユテイレシ
オt1／Ｔは、
t1／Ｔ＝t1／t1＋t2＝C1／C1＋C2 …(1)
となる。このパルス幅信号PWでスイツチSW3が
駆動され、PWがオンのときフイルタ回路FCに
−Es2なる電圧を加え、オフのとき（kEo＋Es1）
なる電圧を加えるので、フイルタ回路FCの出力
には次式に示す如き平均値電圧E3が生ずる。 In the present invention configured in this way, the comparator
When CO output PW is on, SW 1 and SW 2 are on
side, the capacitor C 1 is charged via the resistor R, and the charging voltage Ec 1 rises with the time constant of C 1 R. Since this voltage Ec 1 is the input voltage E 1 of the comparator CO, when Ec 1 increases and exceeds the upper limit value H of CO, the output PW of CO is turned off. CO output
While PW is on, the terminal voltage Ec 2 of capacitor C 2 is OP
follows Ec 1 and always maintains Ec 2 = Ec 1 . CO output PW turns off and SW 1 and SW 2 turn off.
When connected to the OFF side, the electric charge of the capacitor C 2 is discharged through the resistor R, and the voltage Ec 2 of C 2 decreases with the time constant of C 2 R. This Ec 2 is the input voltage of CO E 1
Therefore, when Ec 2 decreases and reaches the lower limit value L, the output PW of CO is turned back on. While the output PW of CO is off, the terminal voltage Ec 1 of capacitor C 1 is
It is followed by OP and always maintains Ec 1 = Ec 2 . In this way, the comparator CO and the switch SW 1 ,
A loop consisting of SW 2 and a pair of capacitors C 1 and C 2 periodically turns on and off and self-oscillates. These relationships are shown in the waveform diagram in Figure 2, where A is the waveform diagram of the input voltage E 1 of the comparator CO, B is the waveform diagram of the comparator output PW, and C is the waveform diagram of the switch SW 1 ,
There is an operating waveform diagram of SW 2 . The time t 1 that the self-excited vibration loop is on is proportional to C 1 R, and the time t 2 that the self-excited vibration loop is off is proportional to C 2 R. Therefore, the duty ratio t 1 /T of the pulse width signal PW of the self-excited oscillation loop is t 1 /T=t 1 /t 1 +t 2 =C 1 /C 1 +C 2 (1). Switch SW 3 is driven by this pulse width signal PW, and when PW is on, a voltage of -Es 2 is applied to the filter circuit FC, and when it is off, a voltage of -Es 2 is applied to the filter circuit FC, and when it is off, (kEo + Es 1 )
As a result, an average voltage E 3 as shown in the following equation is generated at the output of the filter circuit FC.
E3＝C2／C1＋C2・kEo＋C2−αC1／C1＋C2Es1 …(2)
ただし α＝｜Es2｜／｜Es1｜
この平均値電圧E3が増幅器AMPで増幅されて出
力電圧Eoとなるので、AMPのゲインをA1とする
と出力電圧Eoは、
Eo＝A1（C2−αC1）／C1＋C2−kA1C2Es1 …(3)
となる。 E 3 = C 2 /C 1 +C 2・kEo+C 2 −αC 1 /C 1 +C 2 Es 1 …(2) However, α=｜Es 2 |/｜Es 1 | This average voltage E 3 is amplified by the amplifier AMP Therefore, if the gain of AMP is A 1 , the output voltage Eo is Eo=A 1 (C 2 − αC 1 )/C 1 +C 2 −kA 1 C 2 Es 1 …(3) Become.
一方可変コンデンサC1の容量は変位量ｘに対
し、初期容量をCo、可動電極１０と固定電極１
１間の基準間隔をｄ（ｘ＝０のとき）およびスト
レイ容量をCsとすると、
C1＝Coｄ／ｄ＋ｘ＋Cs …(4)
の関係で変化する。よつて出力電圧Eoは、
Eo＝A1｛（C2−αCo−αCs）ｄ＋（C2−αCs）ｘ
｝／（C2＋Co＋Cs−A1kC2）ｄ＋（C2＋Cs−A1kC2）ｘEs
1…(5)
となる。ここで、
Ｋ＝C2＋Cs／A1C2 …(6)
を満足するように係数器Ｋの係数ｋを調整すれ
ば、出力電圧Eoは、
Eo＝A2（１＋A3ｘ／ｄ）Es1 …(7)
ただし
A2＝A1（C2−αCo−αCs）／Co
A3＝C2−αCs／C2−αCo−αCs
となり、しかもCo、Cs、C2、α、ｄ、A1は一定
値であるので、出力電圧Eoは変位量ｘに正確に
対応したものとなる。なお、固定コンデンサC2
の容量をC2＝Co＋Csに選び、かつα＝１になる
ように選べば、出力電圧Eoは、
Eo＝A1ｘ／ｄEs1
となる、また、α＝０とすれば、A3＝１、A2＝
C2／CoA1となり、Es2を零にしても動作できるので、
スイツチSW3のON側を基準点に接続できて負の
基準電源を省略できる。 On the other hand, the capacitance of the variable capacitor C 1 is determined by the initial capacitance Co for the displacement x, the movable electrode 10 and the fixed electrode 1
Assuming that the reference interval between 1 and 1 is d (when x=0) and the stray capacitance is Cs, it changes according to the following relationship: C 1 =Cod/d+x+Cs (4). Therefore, the output voltage Eo is Eo=A 1 {(C 2 −αCo−αCs)d+(C 2 −αCs)x
}/(C 2 +Co+Cs-A 1 kC 2 )d+(C 2 +Cs-A 1 kC 2 )xEs
1 …(5) becomes. Here, if the coefficient k of the coefficient multiplier K is adjusted to satisfy K=C 2 +Cs/A 1 C 2 ...(6), the output voltage Eo will be Eo=A 2 (1+A 3 x/d)Es 1 …(7) However, A 2 = A 1 (C 2 −αCo−αCs)/Co A 3 = C 2 −αCs/C 2 −αCo−αCs, and Co, Cs, C 2 , α, d, A Since 1 is a constant value, the output voltage Eo accurately corresponds to the displacement amount x. In addition, fixed capacitor C 2
If we choose the capacitance of C 2 = Co + Cs and α = 1, the output voltage Eo will be Eo = A 1 x/dEs 1 , and if α = 0, then A 3 = 1 , A 2 =
Since C 2 /CoA is 1 and it can operate even if Es 2 is set to zero, the ON side of switch SW 3 can be connected to the reference point and the negative reference power supply can be omitted.
なお、係数器Ｋの係数値ｋの値をｋ＜C2＋Cs／A1C2
になるように調整すれば、出力電圧Eoの増加率
は変位量ｘが大きくなる程増加し、ｋ＞C2＋Cs／A1C2
に調整すれば変位量ｘが大きくなる程減少するよ
うになり、入出力関係を非直線にできる。しかも
その非直線性の大きさは係数ｋの値を変えること
で設定できる。したがつて、例えば金属ダイヤフ
ラムで差圧や圧力を変位に変換する場合のよう
に、被測定量と可動電極１０の変位量ｘとの非直
線性を補正できる。 Furthermore, if the value of the coefficient value k of the coefficient unit K is adjusted so that k<C 2 +Cs/A 1 C 2 , the increase rate of the output voltage Eo increases as the displacement amount x increases, and k>C If adjusted to 2 + Cs/A 1 C 2 , the larger the displacement x, the smaller it will become, and the input-output relationship can be made non-linear. Furthermore, the magnitude of the nonlinearity can be set by changing the value of the coefficient k. Therefore, it is possible to correct the non-linearity between the amount to be measured and the amount of displacement x of the movable electrode 10, as in the case of converting differential pressure or pressure into displacement using a metal diaphragm, for example.
なお、スイツチSW1，SW2としては電界効果ト
ランジスタ等の電子スイツチが好適であるが、第
３図に示すようにスイツチSW1，SW2としてダイ
オードD1〜D4を用いれば全体構成をさらに簡単
にできる。また、容量をパルス幅信号に変換する
手段としては、第４図に示すように２個の比較器
CO1，CO2とフリツプフロツプFFを用いたもので
あつてもよい。いまFFがセツト状態で、パルス
幅信号PWが発生していると、SW1がオフ、SW2
がオンで、コンデンサC1側が充電され、コンデ
ンサC2側が放電されている。そしてC1側の充電
電圧がC1Rなる時定数で上昇し、CO1の設定値に
達すると、FFがリセツトされ、SW1がオン、
SW2がオフに切替わり、C1側が放電され、C2側
が充電される。その結果C2側の充電電圧がC2Rの
時定数で上昇し、CO2の設定値に達すると、FF
が再びセツトされ、上述の動作を繰り返す。した
がつて、FFがセツトされている時間t1はC1Rに、
オフとなつている時間t2はC2Rにそれぞれ比例
し、FFの出力Ｑにデユテイレシオが１式と同じ
パルス幅信号PWがえられる。またパルス幅信号
PWをフオトカプラ等の絶縁結合手段を介して出
力側に伝達すれば、入出力絶縁ができる。さらに
可変コンデンサC1の初期容量Co等が温度による
影響を受ける場合には、基準電圧Es1を温度に応
じて変化できるように構成すれば有効に温度によ
る影響を補償できる。 Note that electronic switches such as field effect transistors are suitable for the switches SW 1 and SW 2 , but the overall configuration can be further simplified by using diodes D 1 to D 4 as the switches SW 1 and SW 2 as shown in FIG. It's easy to do. In addition, as a means to convert the capacitance into a pulse width signal, two comparators are used as shown in Figure 4.
It may also be one using CO 1 , CO 2 and a flip-flop FF. If FF is currently set and pulse width signal PW is generated, SW 1 is off and SW 2 is off.
is on, the capacitor C1 side is charged and the capacitor C2 side is discharged. Then, the charging voltage on the C 1 side rises with a time constant of C 1 R, and when it reaches the set value of CO 1 , FF is reset and SW 1 is turned on.
SW 2 switches off, the C1 side is discharged and the C2 side is charged. As a result, the charging voltage on the C 2 side increases with the time constant of C 2 R, and when it reaches the set value of CO 2 , the FF
is set again and the above operation is repeated. Therefore, the time t 1 during which FF is set is C 1 R;
The off time t 2 is proportional to C 2 R, and a pulse width signal PW having the same duty ratio as 1 is obtained at the output Q of the FF. Also pulse width signal
Input/output isolation can be achieved by transmitting PW to the output side via an insulating coupling means such as a photocoupler. Furthermore, if the initial capacitance Co, etc. of the variable capacitor C 1 is affected by temperature, the influence of temperature can be effectively compensated by configuring the reference voltage Es 1 so that it can be changed in accordance with the temperature.
以上説明したように本発明においては、被測定
量に応じて変化する容量をパルス幅信号に変換し
た後直流電圧に変換するものにおいて、パルス幅
信号を直流電圧に変換する回路で非直線性を補償
するようにしているので、被測定量に応じて変化
する容量をパルス幅信号に変換する回路として
種々の回路を用いることができ、簡単な構成で非
直線性を有効に補償できる容量式変換器が得られ
る。 As explained above, in the present invention, in a device that converts the capacitance that changes depending on the measured quantity into a pulse width signal and then converts it into a DC voltage, nonlinearity is eliminated in the circuit that converts the pulse width signal into the DC voltage. Since it is designed to compensate, various circuits can be used to convert the capacitance that changes depending on the measured quantity into a pulse width signal, and capacitive conversion can effectively compensate for nonlinearity with a simple configuration. A vessel is obtained.
第１図は本発明変換器の一実施例を示す接続
図、第２図は本発明変換器の動作説明のための波
形図、第３図および第４図は本発明変換器の他の
実施例を示す接続図である。
C1…可変コンデンサ、C2…固定コンデンサ、
CO…比較器、SW1，SW2，SW3…スイツチ、
BA…バツフア増幅器、KC…係数器、AD…加算
器、FC…フイルタ回路、AMP…増幅器、OUT
…出力端子。
FIG. 1 is a connection diagram showing one embodiment of the converter of the present invention, FIG. 2 is a waveform diagram for explaining the operation of the converter of the present invention, and FIGS. 3 and 4 are other embodiments of the converter of the present invention. It is a connection diagram which shows an example. C 1 ... variable capacitor, C 2 ... fixed capacitor,
CO...Comparator, SW 1 , SW 2 , SW 3 ...Switch,
BA...Buffer amplifier, KC...Coefficient unit, AD...Adder, FC...Filter circuit, AMP...Amplifier, OUT
...Output terminal.
Claims (1)
ンサと、固定コンデンサと、前記可変コンデンサ
と固定コンデンサを充放電させ、両コンデンサの
容量の和に対応した周期で、パルス幅が両コンデ
ンサのいずれか一方の容量に対応したパルス幅信
号を得る手段と、このパルス幅信号で駆動され、
帰還電圧と正の基準電圧との和と、零または負の
基準電圧とを切換えてフイルタ回路に与えるスイ
ツチと、前記フイルタ回路の出力に得られる平均
値電圧を前記出力電圧として取り出す手段と、こ
の出力電圧に係数を乗じて前記帰還電圧とする係
数器とを具備し、前記係数器の係数の値を調整し
て非直線性を補償することを特徴とする容量式変
換器。1. Charge and discharge a variable capacitor whose capacitance changes according to the amount to be measured, a fixed capacitor, and the variable capacitor and fixed capacitor, and set the pulse width to either of the two capacitors at a period corresponding to the sum of the capacitances of both capacitors. means for obtaining a pulse width signal corresponding to one of the capacitances;
a switch for switching between the sum of a feedback voltage and a positive reference voltage and a zero or negative reference voltage and applying it to the filter circuit; means for taking out the average value voltage obtained at the output of the filter circuit as the output voltage; A capacitive converter comprising: a coefficient multiplier that multiplies an output voltage by a coefficient to obtain the feedback voltage, and adjusts the value of the coefficient of the coefficient multiplier to compensate for nonlinearity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2575281A JPS57139612A (en) | 1981-02-24 | 1981-02-24 | Capacitance type converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2575281A JPS57139612A (en) | 1981-02-24 | 1981-02-24 | Capacitance type converter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57139612A JPS57139612A (en) | 1982-08-28 |
| JPH0216450B2 true JPH0216450B2 (en) | 1990-04-17 |
Family
ID=12174559
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2575281A Granted JPS57139612A (en) | 1981-02-24 | 1981-02-24 | Capacitance type converter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57139612A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4891267A (en) * | 1985-12-16 | 1990-01-02 | Toho Rayon Co., Ltd. | Carbon fiber cord for rubber reinforcement and process for producing the same |
| FR2920534A1 (en) * | 2007-12-14 | 2009-03-06 | Siemens Vdo Automotive Sas | Position sensor for e.g. clutch pedal, of motor vehicle, has control unit moved along stroke in which state of all-or-nothing signal changes for stroke value when unit is moved in opposed direction from zero to hundred percentage positions |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5161864A (en) * | 1974-11-25 | 1976-05-28 | Shimadzu Corp | Seidenyoryo chokuryudenatsuhenkansochi |
| JPS5252676A (en) * | 1975-10-24 | 1977-04-27 | Yokogawa Hokushin Electric Corp | Capacity-to-electricity converter |
| JPS55159109A (en) * | 1979-05-30 | 1980-12-11 | Yokogawa Hokushin Electric Corp | Capacity type displacement converter |
-
1981
- 1981-02-24 JP JP2575281A patent/JPS57139612A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5161864A (en) * | 1974-11-25 | 1976-05-28 | Shimadzu Corp | Seidenyoryo chokuryudenatsuhenkansochi |
| JPS5252676A (en) * | 1975-10-24 | 1977-04-27 | Yokogawa Hokushin Electric Corp | Capacity-to-electricity converter |
| JPS55159109A (en) * | 1979-05-30 | 1980-12-11 | Yokogawa Hokushin Electric Corp | Capacity type displacement converter |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57139612A (en) | 1982-08-28 |
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