JPS59214784A - Magnetic sensor - Google Patents

Magnetic sensor

Info

Publication number
JPS59214784A
JPS59214784A JP58087571A JP8757183A JPS59214784A JP S59214784 A JPS59214784 A JP S59214784A JP 58087571 A JP58087571 A JP 58087571A JP 8757183 A JP8757183 A JP 8757183A JP S59214784 A JPS59214784 A JP S59214784A
Authority
JP
Japan
Prior art keywords
magnetic field
output
bias
amplifier
magnetic sensor
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
JP58087571A
Other languages
Japanese (ja)
Inventor
Naoto Abe
直人 阿部
Nobuitsu Yamashita
伸逸 山下
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.)
Canon Inc
Original Assignee
Canon Inc
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 Canon Inc filed Critical Canon Inc
Priority to JP58087571A priority Critical patent/JPS59214784A/en
Publication of JPS59214784A publication Critical patent/JPS59214784A/en
Pending legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00Arrangements or instruments for measuring magnetic variables
    • G01R33/02Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09Magnetoresistive devices

Abstract

PURPOSE:To detect a static magnetic field or a magnetic field in a low frequency area at a high accuracy irrelevant to temperature changes by processing output of an AC amplifier for amplifying output of a magnetoresistance effect element (MR element) synchronizing changes in a bias magnetic field. CONSTITUTION:A square wave current equal in the positive and negative absolute value is applied to a bias wire 3 near an MR element 2 from a bias current source 1. The sum of a signal magnetic field S and a bias magnetic field B, the magnetic field S+B is applied to the MR element 2. As a voltage opposite in the polarity at an output terminal (a) is outputted to an output terminal (b) of an AC amplifier 5, an output voltage of a switch 6 to be operated at the same timing as the bias magnetic field shifts to one side so that the output of a low pass filter 7 will turn to a DC output according to the signal magnetic field S clear of a high frequency component. The output will not be affected by the offset of the temperature changes developing as DC component thereby enabling the detection of a magnetic field at a high accuracy without requiring any temperature compensator.

Description

【発明の詳細な説明】 技術分野 本発明は磁気センサ装置に係り、さらに詳細には磁気抵
抗効果素子を用いた磁気センサ装置に関する。
DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a magnetic sensor device, and more particularly to a magnetic sensor device using a magnetoresistive element.

従来技術 近年、t’、’)、 n%’、形成技術の進歩などによ
り、磁気抵抗効果素子(以下MR素子という)を用いた
磁気センサ装置が多用されるようになってきている。
BACKGROUND OF THE INVENTION In recent years, due to advances in formation technology, magnetic sensor devices using magnetoresistive elements (hereinafter referred to as MR elements) have come into widespread use.

最近では、磁気ヘッドなどに加えて、位;僑センサとし
てトルクセンサなどにも用いられるようになってきてお
り、その用途が広がっている。
Recently, in addition to magnetic heads, they have come to be used in torque sensors as position sensors, and their applications are expanding.

第1図(A)にMR素子の模式図を示す。MR素子は同
図に示すようにパーマロイなどの強磁性体をストライプ
状に形成し、その両端に電極を取利用して磁界の変化を
検出するものである6第1図(B)においてグラフの縦
軸は素子の抵抗値変化、横軸は磁界の強さを表わしてい
る。同図に示すように検出の際の抵抗値の変化量は2〜
3%のご〈小さいものである。
FIG. 1(A) shows a schematic diagram of an MR element. As shown in the figure, an MR element is a device in which a ferromagnetic material such as permalloy is formed into a stripe shape, and electrodes are used at both ends to detect changes in the magnetic field.6 In Figure 1 (B), the graph The vertical axis represents the resistance value change of the element, and the horizontal axis represents the strength of the magnetic field. As shown in the figure, the amount of change in resistance value during detection is 2~
3% is small.

このような従来のMR素子を用いた磁気センサは第2図
(A)、(B)に示すような検出特性を有している。第
2図(A)、(B)において縦押1は検出抵抗値、横4
へ11は磁界の’:4f I(Lを示している。
A magnetic sensor using such a conventional MR element has detection characteristics as shown in FIGS. 2(A) and 2(B). In Figure 2 (A) and (B), vertical press 1 is the detection resistance value, horizontal press 4
11 indicates the magnetic field':4f I(L).

また、第2図(A)は検出すべき信号磁界が交流磁界で
ある場合、第2図(B)は信号磁界が静磁界である場合
を示している。両図に示すように、MR素子は抵抗値と
して磁界を検出するため、その検出値に対する温度の影
響は無視することができない。
Further, FIG. 2(A) shows a case where the signal magnetic field to be detected is an alternating magnetic field, and FIG. 2(B) shows a case where the signal magnetic field is a static magnetic field. As shown in both figures, since the MR element detects the magnetic field as a resistance value, the influence of temperature on the detected value cannot be ignored.

第2図(A)に示すように、信号磁界が交がL磁界であ
る場合には、バイアス磁界Bを加えて磁気センサの出力
を交流増幅器により処理し、直流成分を除去することに
よって温度によるオフセット量oSを除去することかで
きる。しかし、信号磁界がf52図(B)に示すような
静磁界である場合や、低い周波数の交流磁界を検出しよ
うとする場合には直が乙増幅器を後段に用いる必要が生
じるので、このような場合には温度変化によるオフセラ
1、 、lid、の影響が出力にそのまま現れてしまう
。そして、MR素子の用いられる領域では、このオフセ
ラミ−量の影響はしばしば信号成分より大きなものにな
る場合が多い。したがって、MR素子を用いた静磁界な
いしは、低周波数領域の磁界を検出するための磁気セン
サ装置においては、温度補償装Ayjや恒温槽などが必
要であるなどの問題があった。
As shown in Figure 2 (A), when the signal magnetic field is an L magnetic field, bias magnetic field B is applied, the output of the magnetic sensor is processed by an AC amplifier, and the DC component is removed. It is also possible to eliminate the offset amount oS. However, if the signal magnetic field is a static magnetic field as shown in Figure 52 (B), or if you are trying to detect a low frequency alternating magnetic field, it will be necessary to use a direct amplifier at the subsequent stage, so such a In this case, the influence of off-cellar 1, , lid, due to temperature change directly appears on the output. In areas where MR elements are used, the effect of this off-ceramic amount is often greater than the signal component. Therefore, in a magnetic sensor device for detecting a static magnetic field or a magnetic field in a low frequency region using an MR element, there are problems such as the need for a temperature compensator Ayj, a constant temperature oven, and the like.

[」的 本発明は以」二の点に鑑みてなされたもので、簡単で安
価な構造により、静磁界ないしは低周波数領域の磁界を
温度変化に関係なく精度よく検出することができる磁気
センサ装置を提供することを1」的とする。
The present invention has been made in view of the following two points, and provides a magnetic sensor device that has a simple and inexpensive structure and can accurately detect static magnetic fields or magnetic fields in the low frequency range regardless of temperature changes. The first objective is to provide the following.

実施例 以下、図面に示す実施例に基づいて本発明の詳細な説明
する。
EXAMPLES Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

第3図に本発明の磁気センサ装置の構成をブロック図に
して示す。図において符号lで示されるものは正負の絶
対値が等しく、検出しようとする信号磁界の周波数より
充分高い周波数の矩形波を発生する発振器などによるバ
イアス電流F流源で、このバイアス電JAE源lで発生
されたバイアス電流はMR素子2近傍に配置されたバイ
アス線3に導かれる。また符号2で示されるものはMR
素子で、磁界変化を電圧変化として取り出すために直流
型rA4が接続されている。これによりMR素子2の抵
抗値変化は電圧変化として取り出され、交流増幅器5に
入力される。
FIG. 3 shows a block diagram of the configuration of the magnetic sensor device of the present invention. What is indicated by the symbol l in the figure is a bias current F source generated by an oscillator or the like that generates a rectangular wave whose positive and negative absolute values are equal and whose frequency is sufficiently higher than the frequency of the signal magnetic field to be detected. The bias current generated is guided to a bias line 3 placed near the MR element 2. Also, those indicated by code 2 are MR
A DC type rA4 is connected to the element in order to extract changes in the magnetic field as changes in voltage. As a result, the resistance value change of the MR element 2 is extracted as a voltage change and is input to the AC amplifier 5.

交流増幅器5は互いに正逆極性の出力端子a。The AC amplifier 5 has output terminals a having positive and opposite polarities.

およびbを有しており、この正逆極圧の出力はスイッチ
6により交互に切り換えられて低域フィルタ7に入力さ
れ、この低域)1ルタ7の出力が磁気センサ装置の出力
となる。この場合、スイッチ6はゲート素子などにより
構成することにより、/ヘイアス電流源1の周波数と同
じ周波数で切り換えられる。また、低域フィルタ7のカ
ッ)・オフ周波数はスイッチ6の切り換え周波数よ辿も
充分低いカットオフ周波数とする。
and b, and the output of the positive and negative extreme pressures is alternately switched by a switch 6 and inputted to a low-pass filter 7, and the output of this low-pass filter 7 becomes the output of the magnetic sensor device. In this case, the switch 6 is configured with a gate element or the like so that it can be switched at the same frequency as the frequency of the heis current source 1. Further, the cut-off frequency of the low-pass filter 7 is set to a cut-off frequency that is sufficiently lower than the switching frequency of the switch 6.

次に上記構成における動作を第4図以下を参照して説明
する。
Next, the operation of the above configuration will be explained with reference to FIG. 4 and subsequent figures.

ここで第4図(A)はバイアス電流源lの出力するバイ
アスの電流変化を、第4図(B)は交流増幅器5の出力
端子aの電圧変化を、また第4図(C)はスイッチ6の
出力電圧の変化を、第4図(D)は低域フィルタ7から
の1・−タル出力電圧をそれぞれ表わしている。さらに
第4図(E)は縦軸にMR素子2の出力端子電圧を、横
軸にそのときMR素子2に加わっている磁界を表わした
ものである。   ゛ 第4図(A)に示されるようにバイアス線3には正負の
絶対値が等しい矩形波の電流が印加される。これによっ
てMR素子2には矩形波のバイアス磁界Bが印加される
。このため、MR素子2にはm4図(E)に示されるよ
うに信号磁界Sとバイアス磁界Bの和の磁界S+Bが印
加されることになる。
Here, FIG. 4(A) shows the change in the bias current output from the bias current source l, FIG. 4(B) shows the voltage change at the output terminal a of the AC amplifier 5, and FIG. 4(C) shows the change in the bias current output from the bias current source 1. 6, and FIG. 4(D) shows the 1-tal output voltage from the low-pass filter 7, respectively. Further, in FIG. 4(E), the vertical axis represents the output terminal voltage of the MR element 2, and the horizontal axis represents the magnetic field applied to the MR element 2 at that time. ``As shown in FIG. 4(A), a rectangular wave current with equal positive and negative absolute values is applied to the bias line 3. As a result, a rectangular wave bias magnetic field B is applied to the MR element 2. Therefore, a magnetic field S+B, which is the sum of the signal magnetic field S and the bias magnetic field B, is applied to the MR element 2 as shown in FIG. m4 (E).

したがって、第4図(B)に示されるように、交流増幅
器5の出力端子aの電圧は、MR素子2に信号磁界Sが
加わっておらず、一定周波数のバイアス磁界Bのみが印
加されている場合には電圧変化がほぼOで、信号磁界S
とバイアス磁界Bの両方が印加されている場合には信号
磁界Sに応じた電圧が発生する。
Therefore, as shown in FIG. 4(B), the voltage at the output terminal a of the AC amplifier 5 is such that no signal magnetic field S is applied to the MR element 2, and only a bias magnetic field B of a constant frequency is applied. In this case, the voltage change is approximately O and the signal magnetic field S
When both the signal magnetic field S and the bias magnetic field B are applied, a voltage corresponding to the signal magnetic field S is generated.

一方、前記のように交流増幅器5の出力端子すには出力
端子aの逆極性の電圧が出力されているので、バイアス
磁界と同タイミングでスイ・ツチングされるスイッチ6
の出力電圧は第4図(C)に示されるように片側にシフ
トされる。したがって、低域フィルタ7からのトータル
出力は第4図(D)に示されるような、変化時の高周波
成分を除去された信号磁界Sに応じた直流出力になる。
On the other hand, as mentioned above, since a voltage with the opposite polarity of the output terminal a is output to the output terminal of the AC amplifier 5, the switch 6 is switched at the same timing as the bias magnetic field.
The output voltage of is shifted to one side as shown in FIG. 4(C). Therefore, the total output from the low-pass filter 7 becomes a DC output corresponding to the signal magnetic field S from which high frequency components at the time of change are removed, as shown in FIG. 4(D).

この出力電圧はMR素子2の抵抗〜磁界特性の直線部分
で動作させるようにすれば信号磁界に比例した出力を(
lIることかできる。
If this output voltage is operated in a straight line between the resistance of the MR element 2 and the magnetic field characteristics, an output proportional to the signal magnetic field will be obtained (
I can do a lot of things.

次に以上の構成で、温度変化があった場合の例を第5図
に示す。
Next, FIG. 5 shows an example where there is a temperature change in the above configuration.

第5図は第2図(A)、(B)および第4図(E)と同
様の線図で、同図に示されるように温度変化によってM
R素子の出力に現われるオフセット量O8は直流成分で
ある。木発明においては前述のような交流増幅器とスイ
ッチによる構成を採用しているので、出力は直流成分と
して現われる温度変化オフセットに影響されることがな
い。したがって、本発明の磁気センサ装置では静磁界お
よび極低周波領域の磁界を検出する際にも従来の直流増
幅式の磁気センサ装置におけるように高温槽や温度補償
などの装置を必要とせずに精度のよい磁界検出を行なう
ことができる。
Figure 5 is a diagram similar to Figures 2 (A), (B), and Figure 4 (E), and as shown in the figure, M
The offset amount O8 appearing in the output of the R element is a DC component. Since the invention employs the configuration of the AC amplifier and switch as described above, the output is not affected by the temperature change offset that appears as a DC component. Therefore, with the magnetic sensor device of the present invention, even when detecting static magnetic fields and magnetic fields in the extremely low frequency range, there is no need for devices such as a high temperature bath or temperature compensation as in conventional DC amplification type magnetic sensor devices. Good magnetic field detection can be performed.

以」−の実施例では、MR素子に対するバイアス磁界発
生のために矩形波電流を用いているが、この波形は矩形
波に限定されるものではなく、正弦波などによる電流で
あってもかまわない。ただし、この場合にも1負の絶対
値の等しい一定レベルの4;”;を用いるのはもちろん
である。この場合にはスイッチ6のかわりにバイアス電
流の正弦波と同一局波数で交流増幅器5の出力を同期検
波し、検波出力を低域フィルタに送ることにより信号磁
界を検出することができ、前述と同様の効果を期待でき
る。
In the following embodiments, a rectangular wave current is used to generate a bias magnetic field for the MR element, but this waveform is not limited to a rectangular wave, and may be a sine wave current or the like. . However, in this case as well, a constant level of 4 with the same absolute value of the negative 1 is used.In this case, instead of the switch 6, the AC amplifier 5 is connected at the same station wave number as the sine wave of the bias current The signal magnetic field can be detected by synchronously detecting the output of and sending the detected output to a low-pass filter, and the same effect as described above can be expected.

以上に示した磁気センサ装置は磁気ヘッド、あるいは磁
気を利用する位置センサなと数々の用途に用いることが
できる。
The magnetic sensor device described above can be used in a number of applications, such as a magnetic head or a position sensor that uses magnetism.

効  果 以上の説明から明らかなように、木発明によれば、磁気
抵抗効果素子を用いた磁気センサ装置において、MR素
子近傍に配置したバイアス磁界発生手段と、MR素子の
出力を増幅する交流増幅器と、この交流増幅器の出力を
前記バイアス磁界の変化と同期して処理する手段とを設
けた構成を採用しているため、簡tJtで安価な構成に
より静磁界ないしは低周波数領域の磁界を温度変化に関
係なく精度よく検出することができる優れた磁気センサ
装置を提供することができる。
Effects As is clear from the above explanation, according to the invention, in a magnetic sensor device using a magnetoresistive element, a bias magnetic field generating means disposed near the MR element and an AC amplifier for amplifying the output of the MR element are used. and a means for processing the output of this AC amplifier in synchronization with the change in the bias magnetic field, the static magnetic field or the magnetic field in the low frequency range can be controlled by temperature changes using a simple and inexpensive configuration. It is possible to provide an excellent magnetic sensor device that can perform accurate detection regardless of the magnetic field.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図(、A)、(B)はそれぞれ磁気抵抗効果素子の
構造および特性を示す模式図および線図、第2図(A)
、(B)は従来の磁気抵抗効果素子を用いた磁気センサ
の特性を示す線図、第3図は本発明の磁気センサ装置の
構成を示すブロック回路図、第4図(A)〜(E)およ
び第5図は本発明の磁気センサ装置の動作を説明する線
図である。 l・・・バイアス電ガCrA   2・・・MR素子3
・・・バイアス線     5・・・交流増幅器6・・
・スイッチ      7・・・低域フィルタA 第2図 (A)           (B) 第3図 第4図 155図 !i 手 糸ゾごネ山 i−,1日 )K−2(1″1効11
1)和58イ17月2711 ’I!+1作庁長官1段 1.7バ件の表示 昭和58年特W順第87571号 2、発明の名称 磁気センサ装置 3、補正をする者 ■件との関係   特許出願人 名  称   (ioo)  キャノン株式会社4、代
理人     電話 03 (268)2481 (イ
0明細書の発明の詳細な説明の欄 図面 6、補正の内容 1)明細書第5頁第6行目から第7行目の「直流電源」
を「直流定電流源」に訂正する。 2)図面中、第4図(A)を別紙の通り訂正する。 第4図(A)
Figures 1 (, A) and (B) are schematic diagrams and diagrams showing the structure and characteristics of the magnetoresistive element, respectively, and Figure 2 (A)
, (B) is a diagram showing the characteristics of a magnetic sensor using a conventional magnetoresistive element, FIG. 3 is a block circuit diagram showing the configuration of the magnetic sensor device of the present invention, and FIGS. ) and FIG. 5 are diagrams explaining the operation of the magnetic sensor device of the present invention. l...Bias voltage CrA 2...MR element 3
...Bias line 5...AC amplifier 6...
・Switch 7...Low pass filter A Fig. 2 (A) (B) Fig. 3 Fig. 4 Fig. 155! i Hand Itozogoneyama i-, 1st) K-2 (1″1 effect 11
1) 和58ii 17月2711 'I! +1 Director General of the Agency 1 paragraph 1.7 Indication of 1985 Special W Order No. 87571 2, Title of invention Magnetic sensor device 3, Person making amendment ■ Relationship with matter Name of patent applicant Name (ioo) Canon stock Company 4, agent Telephone: 03 (268) 2481 (A0 Detailed explanation of the invention in the specification Drawing 6 Contents of amendment 1) “DC power supply” in line 6 to line 7 of page 5 of the specification ”
Correct it to "DC constant current source". 2) In the drawings, Figure 4 (A) will be corrected as shown in the attached sheet. Figure 4 (A)

Claims (3)

【特許請求の範囲】[Claims] (1)磁気抵抗効果素子を用いた磁気センサ装置におい
て、磁気抵抗効果素子近傍に配置したバイアス磁界発生
手段と、磁気抵抗効果素子の出力を増幅する交流増幅器
と、この交流増幅器の出力を前記バイアス磁界の変化と
同期して処理する手段とを設けたことを特徴とする磁気
センサ装置。
(1) In a magnetic sensor device using a magnetoresistive element, there is provided a bias magnetic field generating means disposed near the magnetoresistive element, an AC amplifier that amplifies the output of the magnetoresistive element, and an AC amplifier that applies the bias voltage to the output of the AC amplifier. A magnetic sensor device characterized by comprising means for processing in synchronization with changes in a magnetic field.
(2)前記交流増幅器を互いに逆極性の出力を取り出せ
るものとし、前記の同期処理手段により前記交流増幅器
の逆極性の出力を選択して出力することを特徴とする特
許請求の範囲第1項に記載の磁気センサ装置。
(2) The AC amplifiers are capable of outputs having opposite polarities, and the synchronization processing means selects and outputs the outputs of the AC amplifiers having opposite polarities. The magnetic sensor device described.
(3)前記同期処理手段により前記交流増幅器の出力を
同期検波することを特徴とする特許請求の範囲第1項ま
たは第2項に記載の磁気センサ装置。
(3) The magnetic sensor device according to claim 1 or 2, wherein the output of the AC amplifier is synchronously detected by the synchronization processing means.
JP58087571A 1983-05-20 1983-05-20 Magnetic sensor Pending JPS59214784A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP58087571A JPS59214784A (en) 1983-05-20 1983-05-20 Magnetic sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP58087571A JPS59214784A (en) 1983-05-20 1983-05-20 Magnetic sensor

Publications (1)

Publication Number Publication Date
JPS59214784A true JPS59214784A (en) 1984-12-04

Family

ID=13918681

Family Applications (1)

Application Number Title Priority Date Filing Date
JP58087571A Pending JPS59214784A (en) 1983-05-20 1983-05-20 Magnetic sensor

Country Status (1)

Country Link
JP (1) JPS59214784A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994029740A1 (en) * 1993-06-09 1994-12-22 Imo Institut Für Mikrostrukturtechnologie Und Optoelektronik E.V. Magnetic field sensor composed of a magnetic reversal conductor and one or several magnetoresistive resistances
JP2000055997A (en) * 1998-08-05 2000-02-25 Tdk Corp Magnetic sensor device and current sensor device
CN109269804A (en) * 2018-11-06 2019-01-25 潍柴动力股份有限公司 A kind of Wiring detection method and detection system

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JPS5357810A (en) * 1976-11-04 1978-05-25 Mitsubishi Electric Corp Magnetic head device
JPS53139512A (en) * 1977-05-11 1978-12-05 Mitsubishi Electric Corp Information detector

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JPS5357810A (en) * 1976-11-04 1978-05-25 Mitsubishi Electric Corp Magnetic head device
JPS53139512A (en) * 1977-05-11 1978-12-05 Mitsubishi Electric Corp Information detector

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994029740A1 (en) * 1993-06-09 1994-12-22 Imo Institut Für Mikrostrukturtechnologie Und Optoelektronik E.V. Magnetic field sensor composed of a magnetic reversal conductor and one or several magnetoresistive resistances
US5521501A (en) * 1993-06-09 1996-05-28 Institut Fuer Mikrostrukturtechnologie Und Optoelektronik E.V. Magnetic field sensor constructed from a remagnetization line and one magnetoresistive resistor or a plurality of magnetoresistive resistors
JP2000055997A (en) * 1998-08-05 2000-02-25 Tdk Corp Magnetic sensor device and current sensor device
CN109269804A (en) * 2018-11-06 2019-01-25 潍柴动力股份有限公司 A kind of Wiring detection method and detection system

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