电磁传感器外文翻译.

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传感器(sensor)英文PPT演讲课件

Aplication
A. the sensor does not need to check it agision. General Hall current sensor module’s precision in the work area is higher than 1%, and the precis ion is suitable for any waveform meas urement;
翻译
定义：能感受规定的被测量并按照一定的规律转换成可用输出信号的器件或装置。作用：
探测、感受外界的信号、物理条件（如光、热、湿度）或化学组成（如烟雾），并将探知的信息传递给其他装置或器官。
Light sensor
Light sensor is the most current production, one of the most widely used sensors, it plays
Working principle
Light sensors can converts light signals into electrical signals with photosensitive element sensor , its sensitive wavelengths is close to the visible light wavelength, including infrared wavelengthand ultraviolet wavelengths. Light sensor is not limited to light detection, it also can be used as a detection device of other sensors to test many non-electrical, as long as the nonelectric can be converted into optical signal changes.

电磁感应电磁场英文名词

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4
物理学
第五版
物理学
第五版
物理学名词中英文对照
磁介质磁化强度磁化率分子电流分子磁矩顺磁质抗磁性
magnetic medium magnetization susceptibility molecular current molecular magnetic moment paramagnetism diamagnetism
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3
物理学
第五版
物理学
第五版
物理学名词中英文对照
亨利磁场能量磁能密度
henry magnetic field energy magnetic energy density 位移电流 displacement current 电磁场 electromagnetic field 麦克斯韦 Maxwell,James Clerk 麦克斯韦方程组 Maxwell equations
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6
物理学
第五版
物理学
第五版
物理学名词中英文对照
铁磁质磁场强度
相对磁导率传导电流磁化电流磁畴
ferromagnetic material magnetic field intensity Relative permeability conduction current magnetization current magnetic domain
物理学
第五版
物理学名词中英文对照
楞次楞次定律动生电动势感生电动势有旋电场涡流
Lenz Lenz law motional electromotive force induced electromotive force curl electric field eddy current

（完整版）传感器专业名词英文解释

（完整版）传感器专业名词英⽂解释1. Briefly define the following terms1) TransducerA transducer is a device that converts a signal from one physicalform to a corresponding signal having a different physical form .2) SensorA sensor converts a physical signal into an electrical signal (i.e., amicrophone).3) ActuatorAn actuator is a device that converts electrical energy into physical energy (i.e.,a loudspeaker).4) LinearityThe linearity describes the closeness between the calibration curve and a specified straight line.5) SensitivityThe sensitivity is defined in terms of the relationship between input physicalsignal and output electrical signal. It is generally the ratio between a smallchange in electrical signal to a small change in physical signal. The sensitivity isthe slope of the calibration curve.6) HysteresisThe hysteresis refers to the difference between two output values thatcorrespond to the same input, depending on the direction (increasing ordecreasing) of successive input values. That is, similarly to the magnetizationin ferromagnetic materials, it can happen that the output corresponding to agiven input depends on whether the previous input was higher or lower than thepresent one.Some sensors do not return to the same output value when the input stimulus iscycled up or down. The width of the expected error in terms of the measuredquantity is defined as the hysteresis.7) RepeatabilityThe repeatability is the closeness of agreement between successive resultsobtained with the same method under the same conditions and in a short timeinterval.%100y σ)3~2(δFS ?=Rδ—sample standard deviation8) Strain (mechanical)Fractional change in length ΔL/L.9) Gage factorThe gage factor is defined as the fractional change in resistance divided by the strain.10) Piezoresistive effectThe change in resistivity as a result of a mechanical stress is called thepiezoresistive effect.11)direct piezoelectric effect.the phenomenon of generation of a voltage under mechanical stress is referred to as the piezoelectric effect.12)converse piezoelectric effect.The mechanical strain produced in the crystal under electric stress is called the converse piezoelectric effect.13)Numerical ApertureThe "acceptance cone" defines how much light will be accepted into the fiber andultimately how much remains in the fiber, and is referred to as the numerical aperture. 14)Extrinsic sensorThe optical fiber plays no part in achieving the modulating but simply acts as atransmission medium ; these are extrinsic sensors.15)Intrinsic sensors (fiber optic sensor)The optical fiber plays a major role in modulating the energy from the source; these are referred to as intrinsic sensors.16)Humiditya quantity representing the amount of water vapor in the atmosphere or a gas17)Absolute humidityAbsolute humidity is the mass of water vapor per unit volume of air.18)Relative humidityThe ratio of the actual vapor density to the theoretical maximum (saturation) vapordensity at the same temperature, expressed as a percentage. The relative humidity is the ratio of the actual vapor pressure to the saturation vapor pressure at given temperature. 19)Peltier effectWhen two dissimilar metals are connected together, a small voltage called athermojunction voltage is generated at the junction. This is called the Peltier effect.20)Law of Homogeneous ConductorsFor a given pair of homogeneous conductors forming a closed loop, the Seebeck emf depends only on the temperatures of the junctions, and not on the temperature distribution along the length of the conductors.21)Law of intermediate metalsA third (intermediate) metal wire can be inserted in series with one of the wires withoutchanging the voltage reading (provided that the two new junctions are at the sametemperature).If there is a third metal introduced into the thermocouple circuit , it will not adverselyeffect the reading, if and only if the two junctions of the third metal are at the sametemperatures .22)Bernoulli’s theoremBernoulli’s equation states that energy is approximately conserved across a constriction ina pipe.Bernoulli’s equation: P/(ρ?g) + ?v2/g + y = constant(ρ=density;g=acceleration of gravity ; v=fluid velocity; y=elevation )2. Describe the following devices and how they work1) Strain gageThe strain gauge usually consists of wire, baking, thinpaper, and lead welded. The wireis arranged in the form of a grid in order to obtain higher resistances.2) Parallel plate Capacitive SensorThe parallel plate Capacitive Sensor is a function of the distance d (cm) between theelectrodes of a structure, the surface area A (cm2) of the electrodes, and the permittivity ε0(F/m 1085.812-?for air) of the dielectric between the electrodes; therefore:d Ad AC 0r εεε==3) Differential Capacitive SensorA differential capacitor consists of two variable capacitors so arranged that they undergothe same change, but in opposite directions. The amplifier circuit, depending on itsconfiguration, can generate a voltage proportional to C1 - C2 or C1/C2 or (C1 - C2)/(C1 +C2).4) Variable Reluctance SensorsA typical single-coil variable-reluctance displacement sensor is illustrated in the Figurebelow. The sensor consists of three elements: a ferromagnetic core, a variable air gap, anda ferromagnetic plate.Based on change in the reluctance of a magnetic flux path. Self-inductance L of the coil is: Reluctance can be given as: 5) Variable-Reluctance TachogeneratorsIt consists of a ferromagnetic, toothed wheel attached to a rotating shaft, a coil and amagnet. The wheel rotates in close proximity to the pole piece, thus causing the flux linkedby thecoil to change. The sensors output depends on the speed of the rotation of the wheeland the number of teeth.6) LVDTAn LVDT consists of three coils, a form and a core. The coils are wound on a hollow form.The primary is excited by some ac source. Flux formed by the primary is linked to the twosecondary coils, inducing an ac voltage in each coil. A core is inside the former. It canslide freely through the center of the form.In many applications, the two secondary coils are connected in series opposition.Then the two voltages will subtract; that is, the differential voltage is formed. When thecore is centrally located, the net voltage is zero. When the core is moved to one side, thenet voltage will increase.7) Compression Mode Piezoelectric Accelerometers Upright compression designs sandwich the piezoelectric crystal between a seismic mass2m WL R =0m l R S µµ=and rigid mounting base. A pre- load stud or screw secures the sensing element to themounting base.When the sensor is accelerated, the seismic mass increases or decreases the amount of compression force acting upon the crystal, and a proportional electrical output results.8)Shear mode accelerometerShear mode accelerometer designs bond, or “sandwich,” the sensing material between a center post and seismic mass. A compression ring or stud applies a preload force required to create a rigid linear structure. Under acceleration, the mass causes a shear stress to be applied to the sensing material. This stress results in a proportional electrical output by the piezoelectric material. They represent the traditional or historical accelerometer design.9)PsychrometerA psychrometer contains two identical thermometers. One sensor, the dry bulb ,measures the ambient temperature. The other sensor, the wet bulb, is in a wetted condition.In operation, water evaporation cools the wetted thermometer, resulting in a measurable difference between it and the ambient, or dry bulb measurement. When the wet bulbreaches its maximum temperature depression, the humidity is determined by comparing the wet bulb/dry bulb temperatures on a psychrometric chart10)Dunmore sensorThe Dunmore sensor uses a dilute lithium chloride solution in a polyvinylacetate binder on an insulating substrate. The resistance of the sensor, measured between a bifilar grid, is a function of the r.h. of the surrounding air.11)MOS CapacitorCCDs are typically fabricated on a p-type substrate. In order to implement the “buried” channel a thin n-type region is formed on its surface. A insulator, in the form of a silicon dioxide layer is grown on top of the n-region. Thecapacitor is finished off by placing one or more electrodes, also called gates, on top of the insulating silicon dioxide.12)Full frame transfer (FFT)It consists of a parallel CCD shift register, a serial CCD shift register and a signal sensing output amplifierThe image pixel are vertically transferred into a horizontal serial register, and the charges are horizontally shifted out.13)Interline transfer (ILT)The readout regions are interspaced between the imaging regions, and are shielded from the light.At the end of the integration period, the charges are transferred horizontally to the vertical readout registers in parallel, and then read out line-by-line in a manner similar to FFT.ILT does avoid smear but with the cost of the sensitive imaging areas.14)Frame transfer (FT)The array is grouped into two sections: the image section and the storage section. These two sections are identical, except that the storage section is shielded from the light. During the readout, charges are transfered line-by-line into the storage section by applying the same clocking to both sections. At the end of the integration period, charges in the storagesection are transferred line-by-line a manner similar to FFT.15)proximity sensorsProximity sensors detect objects that are near but without touching them. These sensors are used for near-field robotic operations.16)Time-of-flight sensorsTime-of-flight sensors estimate the range by measuring the time elapsed between thetransmission and return of a pulse17)Triangulation sensorsTriangulation sensors measure range by detecting a given point on the object surface from two different points of view at a known distance from each other. Knowing this distance and the two view angles from the respective points to the aimed surface point, a simple geometrical operation yields the range.18)Thermal Infrared DetectorsThermal infrared detectors convert incoming radiation into heat, raising the temperature of the thermal detector.19)Photon-type detectorsPhoton-type detectors react to the photons emitted by the object. The infrared radiation causes changes in the electrical properties of photon-type detectors.There are two main types of photon infrared detectors. One is called Photoconductive detector, which exhibit increased conductivity with received radiation. Another is named as Photovoltaic detector, this device converts received radiation into electric current.20)shock tubeConstruction of a shock tube is quite simple: it consists of a long tube, closed at both ends, separated into two chambers by a diaphragm, as shown in the Fig. below. A pressure differential is built up across the diaphragm, and the diaphragm is burst, either directly by the pressure differential or initiated by means of an externally controlled probe. Rupturing of the diaphragm causes a shock wave.The shock tube provides the nearest thing to a transient pressure “standard.”21)ThermocoupleA thermocouple consists of two electrical conductors made of different metals that are joined at one end.Note particularly that two junctions are always required. In general, one sense the desired or unknown temperature; this one we shall call the hot or measuring junction. The second will usually be maintained at a known fixed temperature; this one we shall refer to as the cold or reference junction. When the two junctions are at different temperatures, a voltage is developed across the junction.22)Bimetallic strip thermometerTwo dissimilar metals are bonded together into what is called a bimetallic strip. Since two metals have different coefficient of thermal expansion, one metal will expands more than does another metal as temperature increases, causing the bimetallic strip to curl upwards as sketched.23)RTDA resistance temperature detector is basically either a long, small diameter metal wirewound in a coil or an etched grid on a substrate, much like a strain gage. The resistance ofan RTD increases with increasing temperature.24)Three-wire BridgeA clever circuit designed to eliminate the lead wire resistance error is called a three-wireRTD bridge circuit, as sketched to the right.If wires A and B are perfectly matched in length (wires A and B have the same length, and thus the same resistance,), their impedance effects will cancel because each is in anopposite leg of the bridge. The third wire, C, acts as a sense lead and carries no current.25)ThermistorA thermistor is similar to an RTD, but a semiconductor material is usedinstead of a metal. A change in temperature causes the electrical resistance of the semiconductor material to change. P ositive temperature coefficient (PTC) and and negative temperature coefficient (NTC) units are available.26)Seismic (Absolute) Acc eleration PickupsIt consistis of a mass, a spring, and a damper arrangement, as shown in the Figure below.Fig……..y(t）= the absolute displacement of the mass Mx(t）= the absolute displacement of the basez-y=)()(txtz —the relative motion between the mass and the basem —massc —damping constantk —spring constantSeismic (Absolute) Displacement PickupsThe relative displacement z (the output of the sensor) is proportional to the applied displacement. A low value of ωn is needed (ωn should be much less than the lowest vibration frequency for accurate displacement measurement. )Seismic AccelerometerThe relative displacement z ( the output of the sensor) is proportional to the appliedacceleration. a high ωn is needed to measure accurately high-frequency. Increasing ωn will increase the range of frequency for which the amplitude-ratio curve is relatively flat;27)Seismic Velocity Pickup (moving coil type)One type of velocity transducer is based on a linear generator. When a coil cuts the magnetic field lines around a magnet, a voltage is induced in the coil, and this voltage is dependent on the speed of the coil relative to the magnet. The velocity pickup is designed like a displacement pickup, to have a low value of wn and to operate at angular frequencies well above wn so that the motion of the seismic mass is virtually the same as that of the casing but (almost) opposite in phase.28)The Orifice Plate FlowmetersAn orifice plate is a restriction with an opening smaller than the pipe diameter which is inserted in the pipe; Because of the smaller area the fluid velocity increases, causing acorresponding decrease in pressure.The flow ratee can be calculated from the measured pressure drop across the orifice plate 29)Ultrasonic Flowmeters Ultrasonic Doppler Method:Doppler Equation :v f= K ? Δf ;Doppler ultrasonic flowmeters reflect ultrasonic energy from particles, bubbles and/or eddies flowing in the fluid.Ultrasonic Transit-Time Method：The time difference between ultrasonic energy moving upstream and downstream in the fluid is used to determine fluid Velocity.Because transmitter-receiver B is situated downstream withrespect to A, the sound wave train from A to B will arrive soonerthan the train from B to A . This implies that the execution timefrom A to B is shorter than that from B to A.30)Electromagnetic FlowmetersThe measurement principle is based on Faraday’s Law of Magnetic Induction :ahomogeneous magnetic field is built up. An electrically conducting liquid flowsthrough this magnetic field.By the movement of the electrical conductor (liquid) a current gets induced which isproportional to the average flow velocity and the magnet field strength.。

sensor 翻译

sensor 翻译sensor 翻译为传感器，是一种能够感知和测量环境中各种物理量和信号的装置或设备。

传感器通常用于将物理量转换为电信号，然后通过电子电路进行处理和分析。

它广泛应用于各个领域，包括工业自动化、医疗、交通、农业等。

以下是一些常见的传感器及其用法和中英文对照例句：1. 温度传感器 (Temperature Sensor)：用于测量环境或物体的温度。

- The temperature sensor accurately measures the room temperature. (温度传感器准确地测量室温。

)- The car's engine temperature sensor alerted the driver of overheating. (汽车引擎温度传感器提醒驾驶员发生过热。

)2. 光传感器(Light Sensor)：用于检测光照强度或光线的存在与否。

- The light sensor automatically adjusts the screen brightness based on ambient light. (光传感器根据环境光自动调节屏幕亮度。

)- The security system's light sensor triggered the outdoor lights when it detected movement. (安全系统的光传感器在检测到运动时触发室外灯光。

)3. 压力传感器 (Pressure Sensor)：用于测量物体或环境的压力。

- The pressure sensor in the car's tire warns the driver whenthe tire pressure is low. (汽车轮胎的压力传感器在轮胎压力过低时警告驾驶员。

)- The pressure sensor accurately measures the fluid pressure in the pipeline. (压力传感器准确测量管道中的流体压力。

传感器外文翻译文献

传感器外文翻译文献(文档含中英文对照即英文原文和中文翻译)译文：传感器的基础知识传感器是一种将能量转化为光的、机械的或者更为普遍的电信号，这种能量转换发生的过程称之为换能作用。

按照能量转换的复杂程度和控制方式，传感器被分为不同的等级，用来测量位移的电阻式传感器被分类为电阻式位移传感器，其他的分类诸如压力波纹管、压力膜和压力阀等。

1、传感器元件大多数的传感器是由感应元件，转换元件、控制元件、当然也有例外，例如：震动膜、.波纹管、应力管和应力环、低音管和悬臂都是敏感元件。

对物理量作出反应，将物理的压力和力转换为位移，这些转换量可以被用作电参数，如电压、电阻、电容或者感应系数。

机械式和电子式元件合并形成机电式传感设备或传感器。

相似量的结合可以作为能量输入例如：热的、光的、磁的、化学的相互结合产生的热电式、光电式、电磁式和电化学式传感器。

2、传感器灵敏度通过校正测量系统获得的被测物理量和传感器输出信号的关系叫做传感器灵敏度K1=输出信号增量∕被测量的增量，实际上，传感器的灵敏度是已知的通过测量输出信号，输入量由下式决定，输入量=输出信号的增量∕k1。

3、理想传感器的性能特点：a)高保真性：传感器的输出波形式对被测量的真实展现，并且失真很小。

b)被测量干扰最小，任何情况下传感器的精度不能改变。

c)尺寸：必须将传感器正确的放在所需要的场所。

d)被测量和传感器信号之间要有线性关系。

e)传感器对外部变换由很小的灵敏度,例如：压力传感器常常受到外部震动和环境温度的影响f)传感器的固有频率应能够避开被测量的频率和谐波。

4、电传感器电传感器由很多理想特性，它们不仅实现远程测量和显示，还能提供高灵敏度。

电传感器可分为如下两大类。

这些传感器依靠外界电压刺激来工作。

A、变参数型包括：ⅰ）电阻式ⅱ）电容式ⅲ）感应式ⅳ）自感应式ⅴ）互感应式B、自激型包括:ⅰ)电磁式；ⅱ）热电式ⅲ）光栅式；ⅳ）压电式。

这些传感器都是自己产生输出电压来反映被测量的输入并且这些过程是可逆的;例如，一般的电子传感器通常能产生出输出电压来反映晶体材料的性能，.然而，如果在材料上加一个自变电压，传感器可以通过变形或与变电压同频率的振动来体现可逆效应。

传感器中英文介绍

. sensorssensors(English name: transducer/sensor) is a kind of detection device, can feel the measured information, and will feel information transformation according to certain rule become electrical signal output, or other form of information needed to satisfy the information transmission, processing, storage, display, record and control requirements.Sensor's features include: miniaturization, digital, intelligent, multi-functional, systematic and network. It is the first step of automatic detection and automatic control. The existence and development of the sensor, let objects have sensory, such as touch, taste and smell let objects become live up slowly. Usually according to its basic cognitive functions are divided into temperature sensor, light sensor, gas sensor, force sensor, magnetic sensor, moisture sensor, acoustic sensor, radiation sensitive element, color sensor and sensor etc. 10 major categories.temperature transducerTemperature sensors (temperature transducer) refers to can feel temperature translates into usable output signal of the sensor. The temperature sensor is the core part of the temperature measuring instrument, wide variety. According to measuring methods could be divided into two types: contact and non-contact, according to the sensor material and electronic component features divided into two categories, thermal resistance and thermocouple.1 principle of thermocoupleThermocouple is composed of two different materials of metal wire, the welded together at the end. To measure the heating part of the environment temperature, can accurately know the temperature of the hot spots. Because it must have two different material of the conductor, so called the thermocouple. Different material to make the thermocouple used in different temperature range, their sensitivity is also each are not identical. The sensitivity of thermocouple refers to add 1 ℃hot spot temperature changes, the output variation of potential difference. For most of the metal material support thermocouple, this value about between 5 ~ 40 microvolt / ℃.As a result of the thermocouple temperature sensor sensitivity has nothing to do with the thickness of material, use very fine material also can make the temperature sensor. Also due to the production of thermocouple metal materials have good ductility, the slight temperature measuring element has high response speed, can measure the process of rapid change.Its advantages are:(1)high precision measurement. Because of thermocouple direct contact with the object being measured, not affected by intermediate medium.(2)the measurement range. Commonly used thermocouple from 1600 ℃to 50 ℃ ~ + sustainable measurement, some special thermocouple minimum measurable to - 269 ℃ (e.g., gold iron nickel chrome), the highest measurable to + 2800 ℃ (such as tungsten rhenium).(3) simple structure, easy to use. Thermocouple is usually composed of two different kinds of metal wire, but is not limited by the size and the beginning of, outside has protective casing, so very convenient to use. The thermocouple type and structure of the form.2. The thermocouple type and structure formation(1)the types of thermocoupleThe commonly used thermocouple could be divided into two types: standard thermocouple and non-standard thermocouple. Standard thermocouple refers to the national standard specifies its thermoelectric potential and the relationship between temperature, permissible error, and a unified standard score table of thermocouple, it has with matching display instrument to choose from. Rather than a standard thermocouple or on the order of magnitude less than the range to use standardized thermocouple, in general, there is no uniform standard, it is mainly used for measurement of some special occasions.Standardized thermocouple is our country from January 1, 1988, thermocouple and thermal resistance of all production according to IEC international standard, and specify the S, B, E, K, R, J, T seven standardization thermocouple type thermocouple for our country unified design.(2)to ensure that the thermocouple is reliable, steady work, the structure of thermocouple requirements are as follows:①of the two thermocouple thermal electrode welding must be strong;②two hot electrode should be well insulated between each other, in case of short circuit;③compensation wires connected to the free cod of a thermocouple to convenient and reliable;④protect casing thermal electrodes should be able to make sufficient isolation and harmful medium.3.The thermocouple cold end temperature compensationDue to the thermocouple materials are generally more expensive (especiallywhen using precious metals), and the temperature measurement points are generally more far, the distance to the instrument in order to save materials, reduce cost, usually adopt the compensating conductor) (the free end of the cold junction of the thermocouple to the steady control of indoor temperature, connected to the meter terminals. It must be pointed out that the role of the thermocouple compensation wire extension hot electrode, so that only moved to the control room of the cold junction of the thermocouple instrument on the terminal, it itself does not eliminate the cold end temperature change on the influence of temperature, cannot have the compensation effect. So, still need to take some of the other correction method to compensate of the cold end temperature especially when t0 indicates influence on measuring temperature 0 ℃.Must pay attention to when using thermocouple compensating conductor model match, cannot be wrong polarity, compensation conductor should be connected to the thermocouple temperature should not exceed 100 ℃.传感器传感器（英文名称：transducer/sensor）是一种检测装置，能感受到被测量的信息，并能将感受到的信息，按一定规律变换成为电信号或其他所需形式的信息输出，以满足信息的传输、处理、存储、显示、记录和控制等要求。

【精品】电磁学词汇汉英文对照表

【关键字】精品电磁学词汇汉英文对照表A阿伏伽德罗常量Avogadro number安培ampère安培电流ampère – current安培(分子电流)假说ampère hypothesis安培环路定理ampère circuital theorem安全电压safe current安全电流safe currentB百分比（率，数）percent, percentage百万伏特megavolt, megV半波长half – wavelength半导体semiconductor饱和磁化强度saturated magnetization保守力conservative force保障丝fuse wire毕奥一萨伐尔定律Biot一Savart law边界条件boundary condition；比率ratio闭合电路closed circuit避雷针arrester并联电路parallel circuitC场梯度fied gradient充电charging畴domain串联电路series参考系reference system超导体superconductor超导转变温度superconducting transition temperature磁场强度magnetic field intensity磁畴magnetic domain磁单极子magnetic monopole磁导率permeability磁感应强度magnetic induction磁感应线magnetic induction line磁感应管magnetic induction tube磁菏magnetic charge磁化magnetization磁化电流magnetization current磁化率 magnetic susceptibility磁化强度magnetization磁极magnetic pole磁介质magnetic medium磁矩magnetic moment磁通量magnetic flux磁性magnetism磁致伸缩magnetostriction磁滞回线histeresis loopD电磁场electromagnetic field电磁感应electromagnetic induction单位矢量unit vector单位制system of units等势面equipotential surface等势体equipotential body电场electric field电场强度electric field strength电场线electric field line电导conductance电导率conductivity电动势electromotive force电负性electronegativity电功率electric power电荷electric charge电荷量子化charge quantization电荷守恒定律law of conservation of charge 电介质dielectric电矩electric moment电离能energy of ionization电量electric quantity电流electric current电流管current tube电流密度current density电流线lines of current电流元current element电偶极子electric dipole电容capacity电容器capacitor电容率permittivity电势electric potential电势差electric potential difference电势能electric potential energy电通量 electric flux电位移electric displacement电源source电晕electric corona电致伸缩electrostriction电中性electric neutrality电子electron电阻resistance电阻率resistivity叠加原理superposition principleF发电机generator法拉第电磁感应定律Faraday law of electromagnetic induction 分子磁矩molecular magnetic moment分子电流molecular currentG感生电动势induced electromotive force高斯定理Gauss theorem高斯面Gauss surface功work功率power共振resonance轨道磁矩orbital magnetic moment国际单位制（SI）system of international units (SI)过阻尼overdampingH恒流源constant current source恒压源voltage source恒定电流steady current静电力 electrostatic force静电能electrostatic energy静电屏蔽electrostatic screening静电平衡electrostatic equilibrium居里点Curie point绝缘体insulator抗磁性diamagnetism库仑定律Coulomb lawL临界阻尼critical dampingM麦克斯韦速率分布律Maxwell speed distribution摩擦起电electrification by frictionN耐压的voltage-proofO欧姆定律Ohm law偶极子dipoleP匹配match频率frequencyR剩磁remanent magnetismW位移电流displacement current涡流eddy current涡流损耗eddy current loss涡旋电场eddy electric field无功功率reactive powerY压电效应piezoelectific effect有功功率active powerZ自感` self-induction自感`电动势self-induction electromotive force自旋磁矩 spin magnetic moment自由电荷free charge阻尼振动damped vibration附录一科学家中英文姓名对照表安培Ampere, A.M. (1775-1836) 法国培根Bacon,Roger 英国库柏Cooper, L. N.库仑Coulomb, C.A. (1736-1806) 法国居里Curie, P. (1859-1906) 法国爱因斯坦Einstein, Aibert. (1879-1955) 德国法拉第Faraday, M. (1791-1867) 英国菲聂耳Fresnel, A . J. (1788-1827) 法国傅立叶Fourjer, J. B. J. (1768-1830) 法国富兰克林Franklin, B (1706-1790) 美国高斯Gauss,K. F. (1777-1855) 德国盖利克Guoricke, OttoVou (1602-1685) 德国霍耳Hall,E.H. (1855-1938) 美国哈密顿Hamilton, W.R. (1805-1865) 英国亨利Henry, J. (1797-1878) 美国赫姆赫兹Hejmholtz, H. V. (1821-1894) 德国赫兹Hertz, H. R. (1857-1894 德国焦耳Jouje, J. P. (1818-1889) 英国开尔文Kelvin (William Thomson) (1824-1907) 英国朗道Landao, L. D. 俄国拉普拉斯Laplace, P. S. (1749-1827) 法国愣次Lenz, H. F. E. (1804-1865) 法国洛伦兹Lorentz, H. A. (1853-1928) 荷兰麦克斯韦Maxwell, J. C. (1831-1879) 英国迈斯纳Mwissner, W.密立根Millikan, R. A. (1868-1953) 美国奥斯特Oersted, H. G.(1777-1851) 丹麦欧姆Ohm, G. s. (1787-1854) 德国昂纳斯Onnes, H. K. (1853-1926) 荷兰帕尔帖Peltier, J. C. A. (1785-1845) 法国泊松Poisson, S. D. (1781-1840) 法国坡印廷Poynting, J. H. (1852-1914) 英国西门子Siemens, W.斯托克斯Stokes, G. G. (1819-1903) 英国范德格喇夫Van der Graff, R. J. (1901-1967) 美国伏打Volta, C. A. (1745-1827) 意大利瓦特Watt, J. (1736-1819) 英国韦伯Webber, W. E. (1804-1891) 德国此文档是由网络收集并进行重新排版整理.word可编辑版本！。

电磁传感器的工作原理

电磁传感器的工作原理Working Principle of Electromagnetic Sensors。

Electromagnetic sensors are devices that detect and measure electromagnetic fields. They are used in a wide range of applications, from detecting metal objects to measuring the strength of magnetic fields. In this article, we will discuss the working principle of electromagnetic sensors, including their basic components, operation, and applications.Basic Components of Electromagnetic Sensors。

Electromagnetic sensors consist of two basic components: a sensor coil and an oscillator. The sensor coil is a coilof wire that is wound around a core. The core can be madeof various materials, such as iron, ferrite, or air. The oscillator is an electronic circuit that generates an alternating current (AC) signal.Operation of Electromagnetic Sensors。

Electromagnetic sensors work by detecting changes in the magnetic field around the sensor coil. When a magnetic object comes near the sensor coil, it disturbs the magnetic field and causes a change in the voltage across the coil. This change in voltage is detected by the oscillator, which generates a signal that is proportional to the strength of the magnetic field.Applications of Electromagnetic Sensors。

传感器英文翻译

1、Accelerometer Principles67 ratings | 4.01 out of 5| Print DocumentOverviewThis tutorial is part of the National Instruments Measurement Fundamentals series. Each tutorial in this series will teach you a specific topic of common measurement applications by explaining theoretical concepts and providing practical examples. There are several physical processes that can be used to develop a sensor to measure acceleration. In applications that involve flight, such as aircraft and satellites, accelerometers are based on properties of rotating masses. In the industrial world, however, the most common design is based on a combination of Newton's law of mass acceleration and Hooke's law of spring action.Table of Contents1.Spring-Mass System2.Natural Frequency and Damping3.Vibration Effects4.Relevant NI Products5.Buy the BookSpring-Mass SystemNewton's law simply states that if a mass, m, is undergoing an acceleration, a, then there must be a force F acting on the mass and given by F = ma. Hooke's law states that if a spring of spring constant k is stretched (extended) from its equilibrium position for a distance D x, then there must be a force acting on the spring given by F = kDx.FIGURE 5.23 The basic spring-mass system accelerometer.In Figure 5.23a we have a mass that is free to slide on a base. The mass is connected to the base by a spring that is in its unextended state and exerts no force on the mass. In Figure 5.23b, the whole assembly is accelerated to the left, as shown. Now the spring extends in order to provide the force necessary to accelerate the mass. This condition is described by equating Newton's and Hooke's laws:ma = kDx(5.25)where k = spring constant in N/mDx = spring extension in mm = mass in kga= acceleration in m/s2Equation (5.25) allows the measurement of acceleration to be reduced to a measurement of spring extension (linear displacement) becauseIf the acceleration is reversed, the same physical argument would apply, except that the spring is compressed instead of extended. Equation (5.26) still describes the relationship between spring displacement and acceleration.The spring-mass principle applies to many common accelerometer designs. The mass that converts the acceleration to spring displacement is referred to as the test mass or seismic mass. We see, then, that acceleration measurement reduces to linear displacement measurement; most designs differ in how this displacement measurement is made.Natural Frequency and DampingOn closer examination of the simple principle just described, we findanother characteristic of spring-mass systems that complicates the analysis. In particular, a system consisting of a spring and attached mass always exhibits oscillations at some characteristic natural frequency. Experience tells us that if we pull a mass back and then release it (in the absence of acceleration), it will be pulled back by the spring, overshoot the equilibrium, and oscillate back and forth. Only friction associated with the mass and base eventually brings the mass to rest. Any displacement measuring system will respond to this oscillation as if an actual acceleration occurs. This natural frequency is given bywhere f N= natural frequency in Hzk = spring constant in N/mm = seismic mass in kgThe friction that eventually brings the mass to rest is defined by a damping coefficient , which has the units of s-1. In general, the effect of oscillation is called transient response, described by a periodic damped signal, as shown in Figure 5.24, whose equation isX T (t) = Xoe-µt sin(2p f N t) (5.28)where Xr(t) = transient mass positionXo= peak position, initiallyµ = damping coefficientfN= natural frequencyThe parameters, natural frequency, and damping coefficient in Equation (5.28) have a profound effect on the application of accelerometers.Vibration EffectsThe effect of natural frequency and damping on the behavior of spring-mass accelerometers is best described in terms of an applied vibration. If the spring-mass system is exposed to a vibration, then the resultant acceleration of the base is given by Equation (5.23)a(t) = -w2xosin wtIf this is used in Equation (5.25), we can show that the mass motion is given bywhere all terms were previously denned and w= 2p f, with/the applied frequency.FIGURE 5.24 A spring-mass system exhibits a natural oscillation with damping as response to an impulse input.FIGURE 5.25 A spring-mass accelerometer has been attached to a table which is exhibiting vibration. The table peak motion is xand the mass motionois D x.To make the predictions of Equation (5.29) clear, consider the situation presented in Figure 5.25. Our model spring-mass accelerometer has been fixed to a table that is vibrating. The x o in Equation (5.29) is the peak amplitude of the table vibration, and Dx is the vibration of the seismic mass within the accelerometer. Thus, Equation (5.29) predicts that the seismic-mass vibration peak amplitude varies as the vibration frequency squared, but linearly with the table-vibration amplitude. However, this result was obtained without consideration of the spring-mass system natural vibration. When this is taken into account, something quite different occurs.Figure 5.26a shows the actual seismic-mass vibration peak amplitude versus table-vibration frequency compared with the simple frequency squared prediction.You can see that there is a resonance effect when the table frequency equals the natural frequency of the accelerometer, that is, the value of Dx goes through a peak. The amplitude of the resonant peak is determined by the amount of damping. The seismic-mass vibration is described by Equation (5.29) only up to about f N/2.5.Figure 5.26b shows two effects. The first is that the actual seismic-mass motion is limited by the physical size of the accelerometer. It will hit"stops" built into the assembly that limit its motion during resonance. The figure also shows that for frequencies well above the natural frequency, the motion of the mass is proportional to the table peak motion, , but not to the frequency. Thus, it has become a displacement sensor. xoTo summarize:1. f < f N- For an applied frequency less than the natural frequency, the natural frequency has little effect on the basic spring-mass response given by Equations (5.25) and (5.29). A rule of thumb states that a safe maximum applied frequency is f < 1/2.5f N.-For an applied frequency much larger than the natural frequency, 2. f > fNthe accelerometer output is independent of the applied frequency. As shown in Figure 5.26b, the accelerometer becomes a measure of vibration displacement xof Equation (5.20) under these circumstances. It isointeresting to note that the seismic mass is stationary in space in this case, and the housing, which is driven by the vibration, moves about the mass. A general rule sets f > 2.5 f N for this case.Generally, accelerometers are not used near the resonance at their natural frequency because of high nonlinearities in output.FIGURE 5.26 In (a) the actual response of a spring-mass system to vibration is compared to the simple w2prediction In (b) the effect of various table peak motion is shownEXAMPLE 5.14An accelerometer has a seismic mass of 0.05 kg and a spring constant of 3.0 X 103N/m Maximum mass displacement is ±0 02 m (before the mass hits the stops). Calculate (a) the maximum measurable acceleration in g, and (b) the natural frequency.SolutionWe find the maximum acceleration when the maximum displacement occurs, from Equation (5.26).a.or becauseb. The natural frequency is given by Equation (5.27).2、Measuring Pressure with Pressure Sensors79 ratings | 4.00 out of 5| Print DocumentOverviewThis tutorial is part of the National Instruments Measurement Fundamentals series. Each tutorial in this series will teach you a specific topic of common measurement applications by explaining theoretical concepts and providing practical examples. This tutorial introduces and explains the concepts and techniques of measuring pressure with pressure sensors.For more information, return to the NI Measurement Fundamentals Main Page. Table of Contents1.What is Pressure?2.The Pressure Sensor3.Pressure Measurement4.Signal Conditioning for Pressure Sensors5.DAQ Systems for Pressure Measurements6.ReferencesWhat is Pressure?Pressure is defined as force per unit area that a fluid exerts on its surroundings.[1] For example, pressure, P, is a function of force, F, and area, A.P = F/AA container full of gas contains innumerable atoms and molecules that are constantly bouncing of its walls. The pressure would be the average force of these atoms and molecules on its walls per unit of area of the container. Moreover, pressure does not have to be measured along the wall of a container but rather can be measured as the force per unit area along any plane. Air pressure, for example, is a function of the weight of the air pushing down on Earth. Thus, as the altitude increases, pressure decreases. Similarly, as a scuba diver or submarine dives deeper into the ocean, the pressure increases.The SI unit for pressure is the Pascal (N/m2), but other common units of pressure include pounds per square inch (PSI), atmospheres (atm), bars, inches of mercury (in Hg), and millimeters of mercury (mm Hg).A pressure measurement can be described as either static or dynamic. The pressure in cases where no motion is occurring is referred to as static pressure. Examples of static pressure include the pressure of the air inside a balloon or water inside a basin. Often times, the motion of a fluid changes the force applied to its surroundings. Such a pressure measurement is known as dynamic pressure measurement. For example, the pressure inside a balloon or at the bottom of a water basin would change as air is let out of the balloon or as water is poured out of the basin.Head pressure(or pressure head) measures the static pressure of a liquid in a tank or a pipe. Head pressure, P, is a function solely on the height, h, of the liquid and weight density, w, of the liquid being measured as shown in Figure 1 below.Figure 1. Head Pressure MeasurementThe pressure on a scuba diver swimming in the ocean would be the diver's depth multiplied by weight of the ocean (64 pounds per cubic foot). A scuba diver diving 33 feet into the ocean would have 2112 pounds of water on every square foot of his body. The translates to 14.7 PSI. Interestingly enough, the atmospheric pressure of the air at sea level is also 14.7 PSI or 1 atm. Thus, 33 feet of water create as much pressure as 5 miles of air! The total pressure on a scuba diver 33 feet deep ocean would be the combined pressure caused by the weight of the air and the water and would be 29.4 PSI or 2 atm.A pressure measurement can further be described by the type of measurement being performed. There are three types of pressure measurements: absolute, gauge, and differential. Absolute pressure measurement is measured relative to a vacuum as showing in Figure 2 below. Often times, the abbreviations PAA (Pascals Absolute) or PSIA (Pounds per Square Inch Absolute) are use to describe absolute pressure.Figure 2. Absolute Pressure Sensor[3]Gauge pressure is measured relative to ambient atmospheric pressure asshown in Figure 3. Similar to absolute pressure, the abbreviations PAG (Pascals Gauge) or PSIA (Pounds per Square Inch Gauge) are use to describe gauge pressure.Figure 3.Gauge Pressure Sensor[3]Differential pressure is similar to gauge pressure, but instead of measuring relative to ambient atmospheric pressure, differential measurements are taken with respect to a specific reference pressure as shown in Figure 4. Also, the abbreviations PAD (Pascals Differential) or PSID (Pounds per Square Inch Differential) are use to describe differential pressure.Figure 4. Differential Pressure Sensor[3]The Pressure SensorBecause of the great variety of conditions, ranges, and materials for which pressure must be measured, there are many different types of pressure sensor designs. Often pressure can be converted to some intermediate form, such as displacement. The sensor then converts thisdisplacement into an electrical output such as voltage or current. The three most universal types of pressure transducers of this form are the strain gage, variable capacitance, and piezoelectric.Of all the pressure sensors, Wheatstone bridge (strain based) sensors are the most common, offering solutions that meet varying accuracy, size, ruggedness, and cost constraints. Bridge sensors are used for high and low pressure applications, and can measure absolute, gauge, or differential pressure. All bridge sensors make use of a strain gage and a diaphragm as seen in Figure 4.Figure 4. Cross Section of a Typical Strain Gage Pressure Sensor [3]When a change in pressure causes the diaphragm to deflect, a corresponding change in resistance is induced on the strain gauge, which can be measured by a Data Acquisition (DAQ) System. These strain gauge pressure transducers come in several different varieties: the bonded strain gauge, the sputtered strain gauge, and the semiconductor strain gauge.In the bonded strain gauge pressure sensor, a metal foil strain gauge is actually glued or bonded to the surface where strain is being measured. These bonded foil strain gauges (BFSG) have been the industry standard for years and are continually used because of their quick 1000 Hz responsetimes to changes in pressure as well as their large -452°F to -525°F operating temperature.Sputtered strain gauge manufacturers sputter deposit a layer of glass onto the diaphragm and then deposit a thing metal film strain gauge on to the transd ucer’s diaphragm. Sputtered strain gauge sensors actually from a molecular bond between the strain gauge element, the insulating later, and the sensing diaphragm. These gauges are most suitable for long-term use and harsh measurement conditions.Integrated circuit manufacturers have developed composite pressure sensors that are particularly easy to use. These devices commonly employ a semiconductor diaphragm onto which a semiconductor strain gauge and temperature-compensation sensor have been grown. Appropriate signal conditioning is included in integrated circuit form, providing a dc voltage or current linearly proportional to pressure over a specified range.The capacitance between two metals plates changes if the distance between these two plates changes. A variable capacitance pressure transducer, seen in Figure 5 below, measures the change in capacitance between a metal diaphragm and a fixed metal plate. These pressure transducers are generally very stable and linear, but are sensitive to high temperatures and are more complicated to setup than most pressure sensors.Figure 5. Capacitance Pressure Transducer [4]Piezoelectric pressure transducer, as shown in Figure 6, take advantage of the electrical properties of naturally occurring crystals such as quartz. These crystals generate an electrical charge when they are strained. Piezoelectric pressure sensors do not require an externalexcitation source and are very rugged. The sensors however, do require charge amplification circuitry and very susceptible to shock and vibration.Figure 6. Piezoelectric Pressure Transducer [4]A common cause of sensor failure in pressure measurement applications is dynamic impact, which results in sensor overload. A classic example of overloading a pressure sensor is known as the water hammer phenomenon. This occurs when a fast moving fluid is suddenly stopped by the closing of a valve. The fluid has momentum that is suddenly arrested, which causes a minute stretching of the vessel in which the fluid is constrained. This stretching generates a pressure spike that can damage a pressure sensor. To reduce the effects of “water hammer”, sensors are often mounted with a snubber between the sensor and the pressure line. A snubber is usually a mesh filter or sintered material that allows pressurized fluid through but does not allow large volumes of fluid through and therefore prevents pressure spikes in the event of water hammer. A snubber is a good choice to protect your sensor in certain applications, but in many tests the peak impact pressure is the region of interest. In such a case you would want to select a pressure sensor that does not include overprotection. [3]Pressure MeasurementAs described above, the natural output of a pressure transducer is a voltage. Most strain based pressure transducers will output a small mV voltage. This small signal requires several signal conditioning considerations that are discussed in the next section. Additionally, many pressure transducers will output a conditioned 0-5V signal or 4-20 mA current. Both of these outputs are linear across the working range of thetransducer. For example both 0 V and 4 mA correspond to a 0 pressure measurement. Similarly, 5 volts and 20 mA correspond to the Full Scale Capacity or the maximum pressure the transducer can measure. The 0-5V and 4-20 mA signals can easily be measured by National InstrumentsMulti-function Data Acquisition (DAQ) hardware.See Also:Data Acquistion (DAQ) HardwareSignal Conditioning for Pressure SensorsAs with any other bridge based sensor, there are several signal conditioning considerations. To ensure accurate bridge measurements, it is important to consider the following:∙Bridge completion∙Excitation∙Remote sensing∙Amplification∙Filtering∙Offset∙Shunt CalibrationEach of these considerations are addressed thoroughly in the Measuring Strain with Strain Gauges tutorial linked below.Once you have obtained a measurable voltage signal, that signal must be converted to actual units of pressure. Pressure sensors generally produce a linear response across their range of operation, so linearization is often unnecessary, but you will need some hardware or software to convert the voltage output of the sensor into a pressure measurement. The conversion formula you will use depends on the type of sensor you are using, and will be provided by the sensor manufacturer. A typical conversion formula will be a function of the excitation voltage, full scale capacity of the sensor, and a calibration factor.[+] Enlarge ImageFor example, a pressure trandsducer with a full scale capacity of 10,000 PSI and a calibration factor of 3mv/V and given an excitation voltage of 10V DC produces a measured voltage of 15 mV, the measured pressure would be 5000 PSI.After you have properly scaled your signal, it is necessary to obtain a proper rest position. Pressure sensors (whether absolute or gauge) have a certain level that is identified as the rest position, or reference position. The strain gauge should produce 0 volts at this position. Offset nulling circuitry adds or removes resistance from one of the legs of the strain gauge to achieve this "balanced" position. Offset nulling is critical to ensure the accuracy of your measurement and for best results should be performed in hardware rather than software.See Also:Measuring Strain with Strain GaugesDAQ Systems for Pressure MeasurementsUsing SCXI with Pressure MeasurementsNational Instruments SCXI is a signal conditioning system for PC-based data acquisition systems as shown in Figure 7. An SCXI system consists of a shielded chassis that houses a combination of signal conditioning input and output modules, which perform a variety of signal conditioning functions. You can connect many different types of sensors, including absolute and gauge pressure sensors, directly to SCXI modules. The SCXI system can operate as a front-end signal conditioning system for PC plug-in data acquisition (DAQ) devices (PCI and PCMCIA) or PXI DAQ modules.[+] Enlarge ImageFigure 7. A Typical National Instruments SCXI SystemSCXI offers an excellent solution for measuring pressure. The SCXI-1520 universal strain-gauge module is ideal for taking strain based pressure measurements. It provides 8 simultaneous sampled analog input channels each with bridge completion, programmable excitation (0-10 V), remote excitation sensing, programmable gain amplification (1-1000), a programmable 4-pole Butterworth filter (10 Hz, 100 Hz, 1 kHz, 10kHz), offset nulling, and shunt calibration. The SCXI-1314 terminal block provides screw terminals for easy connections to your sensors. Additionally, the SCXI-1314T includes a built-in TEDS reader for Class II bridge-based smart TEDS sensors.Recommended starter kit for Pressure SCXI DAQ System:1.SCXI-1600 DAQ module2.SCXI chassis3.SCXI-1520 modules and SCXI-1314/SCXI-1314T terminal blocks4.Refer to /sensors for recommended sensor vendorsFor a customized solution, see the SCXI Advisor linked below.Using SC Series DAQ with Strain Based Pressure SensorsFor high performance integrated DAQ and signal conditioning, the National Instruments PXI-4220 shown in Figure 8, part of the SC Series, provides an excellent measurement solution. SC Series DAQ offers up to 333 kS/s measurements with 16-bit resolution, and combines data acquisition and signal conditioning into one plug in board. The PXI-4220 is a 200 kS/s, 16 bit DAQ board with programmable excitation, gain, and 4-pole Butterworth filter. Each input channel of the PXI-4220 also includes a 9-pin D-Sub connector for easy connection to bridge sensors, and programmable shunt and null calibration circuitry. The PXI-4220 provides the perfect solution for dynamic pressure measurements with low channel counts.Figure 8. National Instruments PXI-4220Recommended starter kit for Pressure SC Series DAQ System:1.PXI chassis2.PXI embedded controller3.PXI-4220 modules4.Refer to /sensors for recommended sensor vendorsFor a customized solution, see the PXI advisor linked below.Using SCC with Strain Based Pressure SensorsNational Instruments SCC provides portable, modular signal conditioning for DAQ system as seen in Figure 9 below. The SCC series provides a great low channel count and low cost solution that directly interfaces to National Instruments M Series DAQ boards. SCC modules can condition a variety of analog I/O and digital I/O signals, including bridge sensors. SCC DAQ systems include an SC Series shielded carrier such as the SC-2345 or the SC-2350, SCC modules, a cable, and a DAQ device. The SC-2350 shielded carrier provides additional support for TEDS sensors.[+] Enlarge ImageFigure 9. National Instruments SCC Carrier and ModulesThe SCC-SG24 Load Cell Input module accepts up to two full-bridge inputs from load cells or pressure sensors. Each channel of the module includes an instrumentation amplifier, a 1.6 kHz lowpass filter, and a potentiometer for bridge offset nulling. Each SCC-SG24 module also includes a single 10 V excitation source.Recommended Starter Kit for Pressure SCC DAQ System:1.M Series DAQ board2.SC-2345/SC-2350 module carrier3.SCC-SG24 modules (1 per 2 pressure sensors)4.Refer to /sensors for recommended sensor vendorsSee Also:Sensors - Affiliated Product AdvisorsSCXI Product AdvisorPXI Product AdvisorReferences[1] Johnson, Curtis D, “Pressure Principles” Process Control Instrumentation Technology, Prentice Hall PTB.[2] , “Strain Gauge Pressure Transducers”,/products/trans/t-presstrans.htm (current November 2003).[3] , “Honeywell Sensotec Frequently Asked Questions”, /pdf/FAQ_092003.pdf (current November 2003). [4] , "Pressure Measurement: Principles and Practice", /articles/0103/19/main.shtm l (current January 2003).3、Measuring Strain with Strain Gauges896 ratings | 4.27 out of 5| Print DocumentOverviewThis tutorial is part of the National Instruments Measurement Fundamentals series. Each tutorial in this series will teach you a specific topic of common measurement applications by explaining theoretical concepts and providing practical examples.This tutorial introduces and explains the concepts and techniques of measuring strain with strain gauges.You can also view an on demand webcast on strain gauge measurements. For more information, return to the NI Measurement Fundamentals Main Page. Table of Contents1.What Is Strain?2.The Strain Gauge3.Strain Gauge Measurement4.Signal Conditioning for Strain Gauges5.DAQ Systems for Strain Gauge Measurements6.Relevant NI ProductsWhat Is Strain?Strain is the amount of deformation of a body due to an applied force. More specifically, strain (e) is defined as the fractional change in length, as shown in Figure 1 below.Figure 1. Definition of StrainStrain can be positive (tensile) or negative (compressive). Although dimensionless, strain is sometimes expressed in units such as in./in. or mm/mm. In practice, the magnitude of measured strain is very small. Therefore, strain is often expressed as microstrain (me), which is e x 10-6.When a bar is strained with a uniaxial force, as in Figure 1, a phenomenon known as Poisson Strain causes the girth of the bar, D, to contract in the transverse, or perpendicular, direction. The magnitude of this transverse contraction is a material property indicated by its Poisson's Ratio. The Poisson's Ratio n of a material is defined as the negative ratio of the strain in the transverse direction (perpendicular to the force)/e. to the strain in the axial direction (parallel to the force), or n = eT Poisson's Ratio for steel, for example, ranges from 0.25 to 0.3.The Strain GaugeWhile there are several methods of measuring strain, the most common is with a strain gauge, a device whose electrical resistance varies in proportion to the amount of strain in the device. The most widely used gauge is the bonded metallic strain gauge.The metallic strain gauge consists of a very fine wire or, more commonly, metallic foil arranged in a grid pattern. The grid pattern maximizes the amount of metallic wire or foil subject to strain in the parallel direction (Figure 2). The cross sectional area of the grid is minimized to reduce the effect of shear strain and Poisson Strain. The grid is bonded to a thin backing, called the carrier, which is attached directly to the test specimen. Therefore, the strain experienced by the test specimen is transferred directly to the strain gauge, which responds with a linear change in electrical resistance. Strain gauges are available commercially with nominal resistance values from 30 to 3000 Ω, with 120, 350, and 1000 Ω being the most common values.Figure 2. Bonded Metallic Strain GaugeIt is very important that the strain gauge be properly mounted onto the test specimen so that the strain is accurately transferred from the test specimen, through the adhesive and strain gauge backing, to the foil itself.A fundamental parameter of the strain gauge is its sensitivity to strain, expressed quantitatively as the gauge factor (GF). Gauge factor is defined as the ratio of fractional change in electrical resistance to the fractional change in length (strain):The Gauge Factor for metallic strain gauges is typically around 2. Strain Gauge MeasurementIn practice, the strain measurements rarely involve quantities larger than a few millistrain(e x 10-3). Therefore, to measure the strain requires accurate measurement of very small changes in resistance. For example, suppose a test specimen undergoes a strain of 500 me. A strain gauge witha gauge factor of 2 will exhibit a change in electrical resistance of only2 (500 x 10-6) = 0.1%. For a 120 W gauge, this is a change of only 0.12 W.To measure such small changes in resistance, strain gauges are almost always used in a bridge configuration with a voltage excitation source. The general Wheatstone bridge, illustrated below, consists of four resistive arms with an excitation voltage, VEX, that is applied across the bridge.Figure 3. Wheatstone BridgeThe output voltage of the bridge, VO, will be equal to:From this equation, it is apparent that when R1/R2= R4/R3, the voltageoutput VOwill be zero. Under these conditions, the bridge is said to be balanced. Any change in resistance in any arm of the bridge will result in a nonzero output voltage.Therefore, if we replace R4in Figure 3 with an active strain gauge, any changes in the strain gauge resistance will unbalance the bridge and produce a nonzero output voltage. If the nominal resistance of the strain。

(完整版)电磁学词汇汉英文对照表

电磁学词汇汉英文对照表A阿伏伽德罗常量 Avogadro number安培 ampère安培电流 ampère–current安培(分子电流)假说 ampère hypothesis安培环路定理 ampère circuital theorem安全电压 safe current安全电流 safe currentB百分比（率，数） percent, percentage百万伏特 megavolt, megV半波长 half–wavelength半导体 semiconductor饱和磁化强度 saturated magnetization保守力 conservative force保险丝 fuse wire毕奥一萨伐尔定律 Biot一Savart law边界条件 boundary condition；比率 ratio闭合电路 closed circuit避雷针 arrester并联电路 parallel circuitC场梯度 fied gradient充电 charging畴 domain串联电路 series参考系 reference system超导体 superconductor超导转变温度 superconducting transition temperature 磁场强度 magnetic field intensity磁畴 magnetic domain磁单极子 magnetic monopole磁导率 permeability磁感应强度 magnetic induction磁感应线 magnetic induction line磁感应管 magnetic induction tube磁菏 magnetic charge磁化 magnetization磁化电流 magnetization current磁化率magnetic susceptibility磁化强度 magnetization磁极 magnetic pole磁介质 magnetic medium磁矩 magnetic moment磁通量 magnetic flux磁性 magnetism磁致伸缩 magnetostriction磁滞回线 histeresis loopD电磁场 electromagnetic field电磁感应 electromagnetic induction单位矢量 unit vector单位制 system of units等势面 equipotential surface等势体 equipotential body电场 electric field电场强度 electric field strength电场线 electric field line电导 conductance电导率 conductivity电动势 electromotive force电负性 electronegativity电功率 electric power电荷 electric charge电荷量子化 charge quantization电荷守恒定律 law of conservation of charge 电介质 dielectric电矩 electric moment电离能 energy of ionization电量 electric quantity电流 electric current电流管 current tube电流密度 current density电流线 lines of current电流元 current element电偶极子 electric dipole电容 capacity电容器 capacitor电容率 permittivity电势 electric potential电势差 electric potential difference电势能 electric potential energy电通量electric flux电位移 electric displacement电源 source电晕 electric corona电致伸缩 electrostriction电中性 electric neutrality电子 electron电阻 resistance电阻率 resistivity叠加原理 superposition principleF发电机 generator法拉第电磁感应定律 Faraday law of electromagnetic induction 分子磁矩 molecular magnetic moment分子电流 molecular currentG感生电动势 induced electromotive force高斯定理 Gauss theorem高斯面 Gauss surface功 work功率 power共振 resonance轨道磁矩 orbital magnetic moment国际单位制（SI） system of international units (SI)过阻尼 overdampingH恒流源 constant current source恒压源 voltage source恒定电流 steady current静电力electrostatic force静电能 electrostatic energy静电屏蔽 electrostatic screening静电平衡 electrostatic equilibrium居里点 Curie point绝缘体 insulator抗磁性 diamagnetism库仑定律 Coulomb lawL临界阻尼 critical dampingM麦克斯韦速率分布律 Maxwell speed distribution摩擦起电 electrification by frictionN耐压的 voltage-proofO欧姆定律 Ohm law偶极子 dipoleP匹配 match频率 frequencyR剩磁 remanent magnetismW位移电流 displacement current涡流 eddy current涡流损耗 eddy current loss涡旋电场 eddy electric field无功功率 reactive powerY压电效应 piezoelectific effect有功功率 active powerZ自感` self-induction自感`电动势 self-induction electromotive force自旋磁矩spin magnetic moment自由电荷 free charge阻尼振动 damped vibration附录一科学家中英文姓名对照表安培 Ampere, A.M. (1775-1836) 法国培根 Bacon,Roger 英国库柏 Cooper, L. N.库仑 Coulomb, C.A. (1736-1806) 法国居里 Curie, P. (1859-1906) 法国爱因斯坦 Einstein, Aibert. (1879-1955) 德国法拉第 Faraday, M. (1791-1867) 英国菲聂耳 Fresnel, A . J. (1788-1827) 法国傅立叶 Fourjer, J. B. J. (1768-1830) 法国富兰克林 Franklin, B (1706-1790) 美国高斯 Gauss,K. F. (1777-1855) 德国盖利克 Guoricke, OttoVou (1602-1685) 德国霍耳 Hall,E.H. (1855-1938) 美国哈密顿 Hamilton, W.R. (1805-1865) 英国亨利 Henry, J. (1797-1878) 美国赫姆赫兹 Hejmholtz, H. V. (1821-1894) 德国赫兹 Hertz, H. R. (1857-1894 德国焦耳 Jouje, J. P. (1818-1889) 英国开尔文 Kelvin (William Thomson) (1824-1907) 英国朗道 Landao, L. D. 俄国拉普拉斯 Laplace, P. S. (1749-1827) 法国愣次 Lenz, H. F. E. (1804-1865) 法国洛伦兹 Lorentz, H. A. (1853-1928) 荷兰麦克斯韦 Maxwell, J. C. (1831-1879) 英国迈斯纳 Mwissner, W.密立根 Millikan, R. A. (1868-1953) 美国奥斯特 Oersted, H. G.(1777-1851) 丹麦欧姆 Ohm, G. s. (1787-1854) 德国昂纳斯 Onnes, H. K. (1853-1926) 荷兰帕尔帖 Peltier, J. C. A. (1785-1845) 法国泊松 Poisson, S. D. (1781-1840) 法国坡印廷 Poynting, J. H. (1852-1914) 英国西门子 Siemens, W.斯托克斯 Stokes, G. G. (1819-1903) 英国范德格喇夫 Van der Graff, R. J. (1901-1967) 美国伏打 Volta, C. A. (1745-1827) 意大利瓦特 Watt, J. (1736-1819) 英国韦伯 Webber, W. E. (1804-1891) 德国。

传感器中英文介绍

传感器技术外文文献及中文翻译

传感器技术外文文献及中文翻译Sensor technologyA sensor is a device which produces a signal in response to its detecting or measuring a property ,such as position , force , torque , pressure , temperature , humidity , speed , acceleration , or vibration .Traditionally ,sensors (such as actuators and switches )have been used to set limits on the performance of machines .Common examples are (a) stops on machine tools to restrict work table movements ,(b) pressure and temperature gages with automatics shut-off features , and (c) governors on engines to prevent excessive speed of operation . Sensor technology has become an important aspect of manufacturing processes and systems .It is essential for proper data acquisition and for the monitoring , communication , and computer control of machines and systems .Because they convert one quantity to another , sensors often are referred to as transducers .Analog sensors produce a signal , such as voltage ,which is proportional to the measured quantity .Digital sensors have numeric or digital outputs that can be transferred to computers directly .Analog-to-coverter(ADC) is available for interfacing analog sensors with computers .Classifications of SensorsSensors that are of interest in manufacturing may be classified generally as follows:Machanical sensors measure such as quantities aspositions ,shape ,velocity ,force ,torque , pressure , vibration , strain , andmass .Electrical sensors measure voltage , current , charge , and conductivity .Magnetic sensors measure magnetic field ,flux , and permeablity .Thermal sensors measure temperature , flux ,conductivity , and special heat .Other types are acoustic , ultrasonic , chemical , optical , radiation ,laser ,and fiber-optic .Depending on its application , a sensor may consist of metallic , nonmetallic , organic , or inorganic materials , as well as fluids ,gases ,plasmas , or semiconductors .Using the special characteristics of these materials , sensors covert the quantity or property measured to analog or digital output. The operation of an ordinary mercury thermometer , for example , is based on the difference between the thermal expansion of mercury and that of glass.Similarly , a machine part , a physical obstruction , or barrier in a space can be detected by breaking the beam of light when sensed by a photoelectric cell . A proximity sensor ( which senses and measures the distance between it and an object or a moving member of a machine ) can be based on acoustics , magnetism , capacitance , or optics . Other actuators contact the object and take appropriate action ( usually by electromechanical means ) . Sensors are essential to the conduct of intelligent robots , and are being developed with capabilities that resemble those of humans ( smart sensors , see the following ).This is America, the development of such a surgery Lin Bai an example,through the screen, through a remote control operator to control another manipulator, through the realization of the right abdominal surgery A few years ago our country the exhibition, the United States has been successful in achieving the right to the heart valve surgery and bypass surgery. This robot has in the area, caused a great sensation, but also, AESOP's surgical robot, In fact, it through some equipment to some of the lesions inspections, through a manipulator can be achieved on some parts of the operation Also including remotely operated manipulator, and many doctors are able to participate in the robot under surgery Robot doctor to include doctors with pliers, tweezers or a knife to replace the nurses, while lighting automatically to the doctor's movements linked, the doctor hands off, lighting went off, This is very good, a doctor's assistant.Tactile sensing is the continuous of variable contact forces , commonly by an array of sensors . Such a system is capable of performing within an arbitrary three-dimensional space .has gradually shifted from manufacturing tonon-manufacturing and service industries, we are talking about the car manufacturer belonging to the manufacturing industry, However, the services sector including cleaning, refueling, rescue, rescue, relief, etc. These belong to the non-manufacturing industries and service industries, so here is compared with the industrial robot, it is a very important difference. It is primarily a mobile platform, it can move to sports, there are some arms operate, also installed some as a force sensor and visual sensors, ultrasonic ranging sensors, etc. It’s surrounding environment for the conduct of identification, to determine its campaign to complete some work, this is service robot’s one of the basic characteristicsIn visual sensing (machine vision , computer vision ) , cameral optically sense the presence and shape of the object . A microprocessor then processes the image ( usually in less than one second ) , the image is measured , and the measurements are digitized ( image recognition ) .Machine vision is suitable particularly for inaccessible parts , in hostile manufacturing environments , for measuring a large number of small features , and in situations where physics contact with the part may cause damage .Small sensors have the capability to perform a logic function , to conduct two-way communication , and to make a decisions and take appropriate actions . The necessary input and the knowledge required to make a decision can be built into a smart sensor . For example , a computer chip with sensors can be programmed to turn a machine tool off when a cutting tool fails . Likewise , a smart sensor can stop a mobile robot or a robot arm from accidentally coming in contact with an object or people by using quantities such as distance , heat , and noise .Sensor fusion . Sensor fusion basically involves the integration of multiple sensors in such a manner where the individual data from each of the sensors ( such as force , vibration , temperature , and dimensions ) are combined to provide a higher level of information and reliability . A common application ofsensor fusion occurs when someone drinks a cup of hot coffee . Although we take such a quotidian event for granted ,it readily can be seen that this process involves data input from the person's eyes , lips , tongue , and hands .Through our basic senses of sight , hearing , smell , taste , and touch , there is real-time monitoring of relative movements , positions , and temperatures . Thus if the coffee is too hot , the hand movement of the cup toward the lip is controlled and adjusted accordingly .The earliest applications of sensor fusion were in robot movement control , missile flight tracking , and similar military applications . Primarily because these activities involve movements that mimic human behavior . Another example of sensor fusion is a machine operation in which a set of different but integrated sensors monitors (a) the dimensions and surface finish of workpiece , (b) tool forces , vibrations ,and wear ,(c) the temperature in various regions of the tool-workpiece system , and (d) the spindle power .An important aspect in sensor fusion is sensor validation : the failure of one particular sensor is detected so that the control system maintains high reliability . For this application ,the receiving of redundant data from different sensors is essential . It can be seen that the receiving , integrating of all data from various sensors can be a complex problem .With advances in sensor size , quality , and technology and continued developments in computer-control systems , artificial neural networks , sensor fusion has become practical and available at low cost .Movement is relatively independent of the number of components, the equivalent of our body, waist is a rotary degree of freedom We have to be able to hold his arm, Arm can be bent, then this three degrees of freedom, Meanwhile there is a wrist posture adjustment to the use of the three autonomy, the general robot has six degrees of freedom. We will be able to space the three locations, three postures, the robot fully achieved, and of course we have less than six degrees of freedom Fiber-optic sensors are being developed for gas-turbine engines . These sensors will be installed in critical locations and will monitor the conditions inside the engine , such as temperature , pressure , and flow of gas . Continuous monitoring of the signals from thes sensors will help detect possible engine problems and also provide the necessary data for improving the efficiency of the engines .传感器技术传感器一种通过检测某一参数而产生信号的装置。

介绍电磁感应的英语作文高中

Electromagnetic Induction: The Heart ofModern ElectricityElectromagnetic induction, a fundamental concept in physics, lies at the core of our modern electrical era. It describes the phenomenon where a changing magnetic field creates an electric current in a nearby conductor. This remarkable discovery, first made by Michael Faraday in the 19th century, revolutionized the way we generate, transmit, and utilize electrical energy.The principle of electromagnetic induction is straightforward but profound. Imagine a coil of wire placed near a magnet. When the magnet is moved relative to the coil, the magnetic field around the coil changes, inducing an electric current to flow through the wire. This current can then be harnessed for various applications, such as powering electrical devices or charging batteries.The beauty of electromagnetic induction lies in its versatility and efficiency. It allows us to convert mechanical energy into electrical energy, a process known as electromagnetic generation. This is how most of ourpower plants operate, converting the kinetic energy of moving water, steam, or gas turbines into electricity.Moreover, electromagnetic induction plays a crucialrole in transformers, which are essential for increasing or decreasing the voltage of electrical power. Transformersrely on the principle of electromagnetic induction to transfer electrical energy from one circuit to another without a direct electrical connection. This allows us to safely and efficiently distribute electricity over long distances, powering homes, businesses, and industries worldwide.The applications of electromagnetic induction are vast and diverse. It is the backbone of many modern technologies, including electric motors, generators, induction cooktops, and wireless charging systems. Electric motors, which rely on electromagnetic induction to convert electrical energy into mechanical energy, are ubiquitous in our daily lives, powering vehicles, appliances, and even small toys.The significance of electromagnetic induction extends beyond its practical applications. It has deepened our understanding of the fundamental relationships betweenelectricity and magnetism, laying the foundation for advancements in fields like quantum physics and materials science.In conclusion, electromagnetic induction is a pivotal concept that has revolutionized the way we generate, transmit, and use electrical energy. Its widespread applications and profound impact on modern technology underscore its importance in shaping our world. As we continue to explore and harness the power of electromagnetism, electromagnetic induction remains at the forefront of our efforts, driving innovation and progressin the electrical age.**电磁感应：现代电力的核心**电磁感应，物理学中的一个基本概念，是我们现代电力时代的核心所在。

磁电式传感器的工作原理

一、引言磁电式传感器（magnetic-electric sensor）是一种常见的传感器类型，广泛应用于各个领域中，包括工业自动化、交通运输、机器人、医疗设备等。

磁电式传感器利用磁力与电磁感应的原理，将磁场的变化转化为电信号，从而实现对磁场强度、方向或位置的检测。

本文将详细解释磁电式传感器的工作原理，包括其基本原理、结构、工作方式以及应用领域。

二、磁电式传感器的原理1. 电磁感应原理磁电式传感器的工作原理基于电磁感应的原理。

根据法拉第电磁感应定律，当一个导体在磁力线穿过时，会在导体中产生电动势。

这种现象可以用以下公式表示：EMF = -dΦ/dt其中EMF表示电动势，Φ表示磁场通量，dt表示时间的微小变化。

根据该定律可知，当磁场强度或磁场方向发生变化时，会在导体中产生电动势。

2. 磁电效应原理磁电式传感器的核心部件是磁电材料，如铁电材料或磁电材料。

磁电材料具有磁电效应，即在外加磁场的作用下，会产生磁感应强度与电场强度之间的线性关系。

磁电效应可以通过以下公式表示：E = k * H其中E表示电场强度，k表示磁电系数，H表示磁场强度。

根据该公式可知，当磁场强度发生变化时，磁电材料会产生相应的电场强度变化。

3. 磁电式传感器的构成磁电式传感器通常由磁电材料、电极、封装以及相关电路组成。

磁电材料：磁电材料是磁电式传感器的核心部件，它通过磁电效应将磁场的变化转化为电场的变化。

常见的磁电材料包括铁电材料和磁电材料。

电极：电极用于连接磁电材料和外部电路，将磁电材料产生的电场信号引出。

封装：封装是保护磁电材料和电极的外壳，通常采用环氧树脂或金属外壳进行封装。

相关电路：相关电路包括放大电路、滤波电路和输出电路等，用于放大和处理磁电材料产生的电场信号，提供给外部电路使用。

4. 磁电式传感器的工作原理磁电式传感器的工作原理基于磁电效应和电磁感应的原理。

当存在磁场时，磁电材料会产生相应的电场变化。

根据电磁感应原理，当磁场的强度或方向发生变化时，会在磁电材料中产生电动势。

传感器技术外文文献及中文翻译

Sensor technologyA sensor is a device which produces a signal in response to its detecting or measuring a property ,such as position , force , torque ，pressure , temperature ，humidity , speed ，acceleration ，or vibration 。

Traditionally ，sensors （such as actuators and switches )have been used to set limits on the performance of machines .Common examples are (a）stops on machine tools to restrict work table movements ,(b) pressure and temperature gages with automatics shut-off features ，and （c）governors on engines to prevent excessive speed of operation . Sensor technology has become an important aspect of manufacturing processes and systems 。

It is essential for proper data acquisition and for the monitoring ，communication ，and computer control of machines and systems 。

Because they convert one quantity to another , sensors often are referred to as transducers .Analog sensors produce a signal , such as voltage ,which is proportional to the measured quantity .Digital sensors have numeric or digital outputs that can be transferred to computers directly 。

传感器外文翻译

Basic knowledge of transducersA transducer is a device which converts the quantity being measured into an optical, mechanical, or-more commonly-electrical signal. The energy-conversion process that takes place is referred to as transduction.Transducers are classified according to the transduction principle involved and the form of the measured. Thus a resistance transducer for measuring displacement is classified as a resistance displacement transducer. Other classification examples are pressure bellows, force diaphragm, pressure flapper-nozzle, and so on.1、Transducer ElementsAlthough there are exception ,most transducers consist of a sensing element and a conversion or control element. For example, diaphragms,bellows,strain tubes and rings, bourdon tubes, and cantilevers are sensing elements which respond to changes in pressure or force and convert these physical quantities into a displacement. This displacement may then be used to change an electrical parameter such as voltage, resistance, capacitance, or inductance. Such combination of mechanical and electrical elements form electromechanical transducing devices or transducers. Similar combination can be made for other energy input such as thermal. Photo, magnetic and chemical,giving thermoelectric, photoelectric,electromaanetic, and electrochemical transducers respectively.2、Transducer SensitivityThe relationship between the measured and the transducer output signal is usually obtained by calibration tests and is referred to as the transducer sensitivity K1= output-signal increment / measured increment . In practice, the transducer sensitivity is usually known, and, by measuring the output signal, the input quantity is determined from input= output-signal increment / K1.3、Characteristics of an Ideal TransducerThe high transducer should exhibit the following characteristicsa) high fidelity-the transducer output waveform shape be a faithful reproduction of the measured; there should be minimum distortion.b) There should be minimum interference with the quantity being measured; the presence of the transducer should not alter the measured in any way.c) Size. The transducer must be capable of being placed exactly where it is needed.d) There should be a linear relationship between the measured and the transducer signal.e) The transducer should have minimum sensitivity to external effects, pressure transducers,for example,are often subjected to external effects such vibration and temperature.f) The natural frequency of the transducer should be well separated from the frequency and harmonics of the measurand.4、Electrical TransducersElectrical transducers exhibit many of the ideal characteristics. In addition they offer high sensitivity as well as promoting the possible of remote indication or mesdurement. Electrical transducers can be divided into two distinct groups:a) variable-control-parameter types,which include:i)resistanceii) capacitanceiii) inductanceiv) mutual-inductance typesThese transducers all rely on external excitation voltage for their operation.b) self-generating types,which includei) electromagneticii)thermoelectriciii)photoemissiveiv)piezo-electric typesThese all themselves produce an output voltage in response to the measurand input and their effects are reversible. For example, a piezo-electric transducer normally produces an output voltage in response to the deformation of a crystalline material; however, if an alternating voltage is applied across the material, the transducer exhibits the reversible effect by deforming or vibrating at the frequency of the alternating voltage.5、Resistance TransducersResistance transducers may be divided into two groups, as follows:i) Those which experience a large resistance change, measured by using potential-divider methods. Potentiometers are in this group.ii)Those which experience a small resistance change, measured by bridge-circuit methods. Examples of this group include strain gauges and resistance thermometers.5.1 PotentiometersA linear wire-wound potentiometer consists of a number of turns resistance wire wound around a non-conducting former, together with a wiping contact which travels over the barwires. The construction principles are shown in figure which indicate that the wiperdisplacement can be rotary, translational, or a combination of both to give a helical-type motion. The excitation voltage may be either a.c. or d.c. and the output voltage is proportional to the input motion, provided the measuring device has a resistance which is much greater than the potentiometer resistance.Such potentiometers suffer from the linked problem of resolution and electrical noise. Resolution is defined as the smallest detectable change in input and is dependent on thecross-sectional area of the windings and the area of the sliding contact. The output voltage is thus a serials of steps as the contact moves from one wire to next.Electrical noise may be generated by variation in contact resistance, by mechanical wear due to contact friction, and by contact vibration transmitted from the sensing element. In addition, the motion being measured may experience significant mechanical loading by the inertia and friction of the moving parts of the potentiometer. The wear on the contacting surface limits the life of a potentiometer to a finite number of full strokes or rotations usually referred to in the manufacture’s specification as the ‘number of cycles of life expectancy’, a typical value being 20*1000000 cycles.The output voltage V0 of the unload potentiometer circuit is determined as follows. Let resistance R1= xi/xt *Rt where xi = input displacement, xt= maximum possible displacement, Rt total resistance of the potentiometer. Then output voltage V0= V*R1/(R1+( Rt-R1))=V*R1/Rt=V*xi/xt*Rt/Rt=V*xi/xt. This shows that there is a straight-line relationship between output voltage and input displacement for the unloaded potentiometer.It would seen that high sensitivity could be achieved simply by increasing the excitation voltage V. however, the maximum value of V is determined by the maximum power dissipation P of the fine wires of the potentiometer winding and is given by V=(PRt)1/2 .5.2 Resistance Strain GaugesResistance strain gauges are transducers which exhibit a change in electrical resistance in response to mechanical strain. They may be of the bonded or unbonded variety .a) bonded strain gaugesUsing an adhesive, these gauges are bonded, or cemented, directly on to the surface of the body or structure which is being examined.Examples of bonded gauges arei) fine wire gauges cemented to paper backingii) photo-etched grids of conducting foil on an epoxy-resin backingiii)a single semiconductor filament mounted on an epoxy-resin backing with copper or nickel leads.Resistance gauges can be made up as single elements to measuring strain in one direction only,or a combination of elements such as rosettes will permit simultaneous measurements in more than one direction.b) unbonded strain gaugesA typical unbonded-strain-gauge arrangement shows fine resistance wires stretched around supports in such a way that the deflection of the cantilever spring system changes the tension in the wires and thus alters the resistance of wire. Such an arrangement may be found in commercially available force, load, or pressure transducers.5.3 Resistance Temperature TransducersThe materials for these can be divided into two main groups:a) metals such as platinum, copper, tungsten, and nickel which exhibit and increase in resistance as the temperature rises; they have a positive temperature coefficient of resistance.b) semiconductors, such as thermistors which use oxides of manganese, cobalt, chromium, or nickel. These exhibit large non-linear resistance changes with temperature variation and normally have a negative temperature coefficient of resistance.a) metal resistance temperature transducersThese depend, for many practical purpose and within a narrow temperature range, upon the relationship R1=R0*[1+a*(b1-b2)] where a coefficient of resistance in ℃-1,and R0 resistance in ohms at the reference temperature b0=0℃ at the reference temperature range ℃.The international practical temperature scale is based on the platinum resistance thermometer, which covers the temperature range -259.35℃ to 630.5℃.b) thermistor resistance temperature transducersThermistors are temperature-sensitive resistors which exhibit large non-liner resistance changes with temperature variation. In general, they have a negative temperature coefficient. For small temperature increments the variation in resistance is reasonably linear; but, if large temperature changes are experienced, special linearizing techniques are used in the measuring circuits to produce a linear relationship of resistance against temperature.Thermistors are normally made in the form of semiconductor discs enclosed in glass vitreous enamel. Since they can be made as small as 1mm,quite rapid response times are possible.5.4 Photoconductive CellsThe photoconductive cell , uses a light-sensitive semiconductor material. The resistance between the metal electrodes decrease as the intensity of the light striking the semiconductor increases. Common semiconductor materials used for photo-conductive cells are cadmium sulphide, lead sulphide, and copper-doped germanium.The useful range of frequencies is determined by material used. Cadmium sulphide is mainly suitable for visible light, whereas lead sulphide has its peak response in the infra-red regionand is, therefore , most suitable for flame-failure detection and temperature measurement. 5.5 Photoemissive CellsWhen light strikes the cathode of the photoemissive cell are given sufficient energy to arrive the cathode. The positive anode attracts these electrons, producing a current which flows through resistor R and resulting in an output voltage V.Photoelectrically generated voltage V=Ip.RlWhere Ip=photoelectric current(A),and photoelectric current Ip=Kt.BWhere Kt=sensitivity (A/im),and B=illumination input (lumen)Although the output voltage does give a good indication of the magnitude of illumination, the cells are more often used for counting or control purpose, where the light striking the cathode can be interrupted.6、Capacitive TransducersThe capacitance can thus made to vary by changing either the relative permittivity, the effective area, or the distance separating the plates. The characteristic curves indicate that variations of area and relative permittivity give a linear relationship only over a small range of spacings. Thus the sensitivity is high for small values of d. Unlike the potentionmeter, the variable-distance capacitive transducer has an infinite resolution making it most suitable for measuring small increments of displacement or quantities which may be changed to produce a displacement.7、Inductive TransducersThe inductance can thus be made to vary by changing the reluctance of the inductive circuit. Measuring techniques used with capacitive and inductive transducers:a)A.C. excited bridges using differential capacitors inductors.b)A.C. potentiometer circuits for dynamic measurements.c) D.C. circuits to give a voltage proportional to velocity for a capacitor.d) Frequency-modulation methods, where the change of C or L varies the frequency of an oscillation circuit.Important features of capacitive and inductive transducers are as follows:i)resolution infiniteii) accuracy+- 0.1% of full scale is quotediii)displacement ranges 25*10-6 m to 10-3miv) rise time less than 50us possibleTypical measurands are displacement, pressure, vibration, sound, and liquid level.8、Linear Variable-differential Ttransformer9、Piezo-electric Transducers10、Electromagnetic Transducers11、Thermoelectric Transducers12、Photoelectric Cells13、Mechanical Transducers and Sensing Elements传感器的基础知识传感器是一种把被测量转换为光的、机械的或者更平常的电信号的装置。

传感器英语

nication is one of the most significant operations in WSNs and requires a huge portion of the overall energy consumption. Indeed, the energy required for data communication is far greater than the energy required for data processing in a sensor node.
当这些设备部署在一个广泛的地理区域时，它们可以收集关于环境的信息，并通过形成一个分布式通信网络，既无线传感器网络（WSM）有效地协作处理这些信息，如图1.1所示。
A WSN is a special case of an ad-hoc wireless network, and assumes a multi-hop communication framework with no common infrastructure, where the sensors spontaneously cooperate to deliver information by forwarding packets from a source to a destination.
无线传感器网络
WIRELESS SENSOR NETWORKS
vocabulary
sensor
[ˈsensə(r)]
deploy
[dɪˈplɔɪ]
collaborate
[kəˈlæ bəreɪt]
illustrate
[ˈɪləstreɪt]
status
[ˈsteɪtəs]

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