關(guān)于磁性傳感器，你想知道的在這里（中英文）
磁性傳感器是檢測(cè)磁鐵或電流產(chǎn)生的磁力和地磁力大小的傳感器。有許多不同類型的磁性傳感器。
本節(jié)介紹典型的傳感器類型及其特性。
A magnetic sensor is a sensor that detects the magnitude of magnetism and geomagnetism generated by a magnet or current. There are many different types of magnetic sensors.
This section explains the typical sensor types and their features.
線圈 / Coiled
線圈是可以檢測(cè)磁通密度變化的簡(jiǎn)單磁性傳感器。如圖所示，當(dāng)磁鐵靠近線圈時(shí)，線圈中的磁通密度增加ΔB。然后，在線圈中產(chǎn)生在阻礙磁通密度增加的方向上產(chǎn)生磁通的感應(yīng)電動(dòng)勢(shì)/感應(yīng)電流。相反，將磁鐵移離線圈會(huì)降低線圈中的磁通密度，因此線圈中會(huì)產(chǎn)生感應(yīng)電動(dòng)勢(shì)和感應(yīng)電流，從而增加磁通密度。
Coils are the simple magnetic sensors that can detect changes of the magnetic flux density. As shown in the figure, when a magnet is brought close to the coil, the magnetic flux density in the coil increases by ΔB. Then, an induced electromotive force/induced current that generates a magnetic flux in a direction that hinders an increase in magnetic flux density is generated in the coil. Conversely, moving the magnet away from the coil reduces the magnetic flux density in the coil, so induced electromotive force and induced current will be generated in the coil to increase the magnetic flux density.
而且，當(dāng)磁體不移動(dòng)時(shí)磁通密度沒(méi)有變化，因此不會(huì)產(chǎn)生感應(yīng)電動(dòng)勢(shì)或感應(yīng)電流。通過(guò)測(cè)量該感應(yīng)電動(dòng)勢(shì)的方向和大小，可以檢測(cè)磁通密度的變化。
由于其結(jié)構(gòu)簡(jiǎn)單，線圈不易損壞。然而，輸出電壓取決于磁通量的變化率。可能無(wú)法使用線圈來(lái)檢測(cè)固定磁鐵或變化非常緩慢的磁通量。
Also, since there is no change in the magnetic flux density when the magnet is not moved, no induced electromotive force or induced current will be generated. By measuring the direction and magnitude of this induced electromotive force, it is possible to detect the change in magnetic flux density.
Because of its simple structure, a coil is not easily damaged. However, the output voltage depends on the rate of change of the magnetic flux. It may not be possible to use a coil to detect a fixed magnet or magnetic flux that changes very slowly.
干簧管（磁簧開關(guān)） / Reed Switch
干簧管是一種傳感器，將從左右兩側(cè)伸出的金屬片（簧片）封裝在玻璃管內(nèi)，在簧片重疊的位置處留有間隙。當(dāng)外部施加磁場(chǎng)時(shí)，這些簧片就會(huì)被磁化。當(dāng)簧片被磁化時(shí)，重疊部分相互吸引并接觸，然后開關(guān)接通。
A reed switch is a sensor in which metal pieces (reed) extending from both the left and right sides are enclosed in a glass tube with a gap at the overlapping position of the reeds. When a magnetic field is applied externally, these reeds are magnetized. When the reeds are magnetized, the overlapping parts attract each other and come into contact, then the switch turns on.
霍爾元件 / Hall Elements
霍爾元件是利用霍爾效應(yīng)的器件?！癏all”源自霍爾博士發(fā)現(xiàn)霍爾效應(yīng)的名字。它基于這樣的現(xiàn)象：當(dāng)向電流流過(guò)的物體施加垂直于電流的磁場(chǎng)時(shí)，電動(dòng)勢(shì)出現(xiàn)在與電流和磁場(chǎng)都正交的方向上。
當(dāng)電流施加到薄膜半導(dǎo)體時(shí)，通過(guò)霍爾效應(yīng)輸出與磁通密度及其方向相對(duì)應(yīng)的電壓。霍爾效應(yīng)用于檢測(cè)磁場(chǎng)（如圖所示）。
A Hall element is a device that uses the Hall effect. “Hall” came from Dr. Hall's name for discovering Hall effect. It is based on the phenomenon that the electromotive force appears in the direction orthogonal to both the current and the magnetic field when applying a magnetic field perpendicular to the current to the object through which current is flowing.
When a current is applied to a thin film semiconductor, a voltage corresponding to the magnetic flux density and its direction is output by the Hall effect. The Hall effect is used to detect a magnetic field, (shown in the figure).
霍爾元件即使在磁通密度沒(méi)有變化的靜態(tài)磁場(chǎng)的情況下也可以檢測(cè)磁場(chǎng)。因此，霍爾元件被用于各種應(yīng)用，例如與磁鐵組合使用的非接觸式開關(guān)、角度傳感器和電流傳感器。使用霍爾元件的地磁傳感器廣泛用于智能手機(jī)和其他應(yīng)用。
Hall elements can detect a magnetic field even in the case of a static magnetic field with no change in magnetic flux density. Therefore, Hall elements are used in various applications, such as non-contact switches used in combination with magnets, angle sensors, and current sensors. Geomagnetic sensors using Hall elements are widely used in smartphones and other applications.
磁阻元件 / Magnetoresistive Element
使用材料檢測(cè)磁場(chǎng)的元件，當(dāng)施加磁力時(shí)電阻會(huì)發(fā)生變化，這種元件稱為磁阻（MR）元件。
除了半導(dǎo)體磁阻元件(SMR)之外，作為使用鐵磁薄膜材料的磁阻元件的代表示例，還有各向異性磁阻元件（AMR）、巨磁阻元件（GMR）和隧道磁阻元件（TMR）三種傳感器。
An element that detects a magnetic field using a material, that resistance changes when magnetic force is applied, is called a magnetoresistive, (MR), element.
Other than semiconductor magnetoresistive element, (SMR), there are three kinds of sensors as representative examples of the magnetoresistive element using a ferromagnetic thin film material such as anisotropic magnetoresistive element, (AMR), giant magnetoresistive element, (GMR), and tunnel magnetoresistive element, (TMR).
半導(dǎo)體磁阻元件（SMR）
Semiconductor Magnetoresistive Element (SMR)
霍爾元件是測(cè)量洛倫茲力產(chǎn)生的霍爾電壓的傳感器，而磁阻元件是利用洛倫茲力引起的電阻值變化的傳感器。下圖顯示了AKM也生產(chǎn)的N型半導(dǎo)體磁阻元件（SMR：半導(dǎo)體磁阻）的電阻值如何變化。SMR結(jié)構(gòu)中，金屬電極放置在半導(dǎo)體薄膜上。當(dāng)如圖所示的順時(shí)針?lè)较虻碾娏髁鬟^(guò)半導(dǎo)體薄膜時(shí)，作為N型半導(dǎo)體的載流子的電子逆時(shí)針?lè)较蛄鲃?dòng)，將矢量的速度設(shè)為“v”。當(dāng)施加如圖所示方向的磁場(chǎng) B 時(shí)，電子受到洛倫茲力，路徑隨著彎曲而變長(zhǎng)，
Whereas the Hall element is a sensor that measures the Hall voltage generated by the Lorentz force, the magnetoresistive element is a sensor that utilizes the change in the resistance value caused by the Lorentz force. The following figure shows how the resistance value of an N-type semiconductor magnetoresistive element (SMR: Semiconductor Magnetoresistive), which AKM also produces, changes. Metal electrodes are placed on a semiconductor thin film in the structure of SMR. When a clockwise current as shown in the figure flows through the semiconductor thin film, electrons which are carriers of N-type semiconductors flow counterclockwise, and the velocity of the vector is assumed as "v". When applying a magnetic field B oriented as shown in the figure, electrons undergo Lorentz force and the path becomes longer as being bent, so that the resistance value increases.
各向異性磁阻元件 (AMR)
Anisotropic Magnetoresistive Eelement (AMR)
電子的散射程度在強(qiáng)磁性膜的磁化方向與電流方向平行的情況(a)和磁化方向與電流方向垂直的情況(b)之間變化。因此，電阻值也會(huì)發(fā)生變化。
The scattering degree of electro changes between the case (a) where the magnetization direction of the ferromagnetic film is parallel to the direction of current and the case (b) where the direction of magnetization is vertical to the current direction. Therefore, the resistance value also changes.
巨磁阻元件 (GMR)
Giant Magnetoresistive Element (GMR)
在鐵磁材料（固定層）、非磁性金屬和鐵磁材料（自由層）的層疊膜的情況下，電子的散射程度根據(jù)固定層和自由層的磁化方向是否反平行而變化(a) 或平行 (b)。因此，電阻值發(fā)生變化。
In the case of a laminated film of ferromagnetic material, (pinned layer), nonmagnetic metal and ferromagnetic material, (free layer), the scattering degree of electron changes depending on if the direction of magnetization of the pinned layer and the free layer are antiparallel (a) or parallel (b). Therefore, the resistance value changes.
隧道磁阻元件 (TMR)
Tunnel Magnetoresistive Element (TMR)
在鐵磁材料（固定層）、絕緣體和鐵磁材料（自由層）的層疊膜的情況下，穿過(guò)絕緣體的電子比例由于隧道效應(yīng)而變化，并且電阻值根據(jù)方向而變化固定層和自由層的磁化強(qiáng)度是反平行(a)或平行(b)。
In the case of a laminated film of ferromagnetic material, (pinned layer), insulator and ferromagnetic material, (free layer), the proportion of electrons passing through the insulator changes due to the tunnel effect and the resistance value changes depending on if the direction of magnetization of the pinned layer and the free layer are antiparallel (a) or parallel (b).
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