《电气工程与自动化专业英语 》 课件 Chapter01 Circuit Fundamentals 电路基础

电气工程及其自动化专业英语

Chapter1CircuitFundamentals电路基础1.内容简介

本章主要介绍电荷；导体、绝缘体、半导体；电流、电压、电阻的概念；电阻、电压、电流的测试方法；直流串联电路和交流电路基本原理等内容。2.文中涉及理论知识可参考《电路》中有关内容。3.生词与短语1．electrostaticadj.静电的2．chargen.电荷3．positiveadj.正的4．negativeadj.负的5．electronn.电子6．protonn.质子7．gravitationaladj.引力的8．precipitatorn.电滤器9．powerplant发电厂10.currentn.电流11．conductorn.导体12．insulatorn.绝缘体13．semiconductorn.半导体14．valenceshell价电子层

Chapter1CircuitFundamentals15．Siliconn.硅16．germaniumn.锗17．seleniumn.硒18．voltagen.电压19．resistancen.电阻20．circuitn.电路21．electromotiveforce(EMF)电动势22．repelv.排斥23．multimetern.万用表24．milliammetern.毫安表

Chapter1CircuitFundamentals25．ammetern.安培表26．ohmmetern.欧姆表27．voltmetern.电压表28．polarityn.极性29．paralleln.并联30．seriesn.串联31．filamentn.灯丝32．resistorn.电阻器33．phasen.相位34．hotwire火线

Chapter1CircuitFundamentals35．neutralwire中线36．electricalpower电源4.重点句子翻译[1]However,apositivechargeistheoppositeofanegativecharge.Thesechargesarecalledelectrostaticcharges.Eachchargedparticleissurroundedbyanelectrostaticfield.

然而，正电荷与负电荷的极性是相反的。这些电荷被称为静电荷。每一个带电粒子被静电场围绕着。

Chapter1CircuitFundamentalsChapter1CircuitFundamentals[2]Theeffectthatelectrostaticchargeshaveoneachotherisveryimportant.Theyeitherrepel(moveaway)orattract(cometogether)eachother.Itissaidthatlikechargesrepelandunlikechargesattract.静电荷彼此之间的影响是很重要的。它们或者排斥（远离），或者吸引（聚集）。这就是通常人们所说的同性排斥，异性相吸。[3]Itisalsopossibletochargeothermaterialsbecausesomematerialsarechargedwhentheyarebroughtclosetoanotherchargedobject.Ifachargedrubberrodistouchedagainstanothermaterial,thesecondmaterialmaybecomecharged.

当一些材料与另一带电体接近时就会带上电荷，所以它也可能使其它材料带上电荷。如果带电的橡胶棒与另一种材料接触，就可能使这种材料带上电荷。

Chapter1CircuitFundamentals[4]Electricalchargesareusedtofilterdustandsootindevicescalledelectrostaticfilters.Electrostaticprecipitatorsareusedinpowerplantstofiltertheexhaustgasthatgoesintotheair.在被称为静电过滤器的设备中，使用电荷来滤除灰尘和烟灰。在电厂，使用静电滤器过滤排放到空气中的废气。

Chapter1CircuitFundamentals[5]Conductorsaresaidtohavelowresistancetoelectricalcurrentflow.Conductorsusuallyhavethreeorfewerelectronsintheouterorbitoftheiratoms.导体对流通的电流阻力小。导体原子的外层轨道通常有三个或少于三个的电子。[6]Theelectronsofmaterialsthatareinsulatorsaredifficulttorelease.Insomeinsulators,theirvalenceshellsarefilledwitheightelectrons.Thevalenceshellsofothersareoverhalf-filledwithelectrons.Theatoms

Chapter1CircuitFundamentals绝缘体材料的电子难于释放。在一些绝缘体里，它们的价电子层填充有八个电子。其它绝缘体的价电子层也填充有一半以上的电子。绝缘体材料的原子据说是稳定[7]Semiconductormaterialsareneitherconductorsnorinsulators.Theirclassificationalsodependsonthenumberofelectronsthattheiratomshaveintheirvalenceshells.Semiconductorshave4electronsintheirvalenceshells.

Chapter1CircuitFundamentals

半导体材料既不是导体，也不是绝缘体。它们的分类取决于原子的价电子层电子的数量。半导体原子的价电子层有四个电子。[8]Staticelectricityiscausedbystationarycharges.However,electricalcurrentisthemotionofelectricalchargesfromonepointtoanother.Electriccurrentisproducedwhenelectrons(-)areremovedfromtheiratoms.

Chapter1CircuitFundamentalsChapter1CircuitFundamentals

静电是由静止的电荷产生的。然而，电流是由电荷从一点到另一点的运动产生的。当电子从它们的的原子移除时，就会产生电流。[9]Themovementofvalenceshellelectronsofconductorsproduceselectricalcurrent.Theouterelectronsoftheatomsofaconductorarecalledfreeelectrons.Energyreleasedbytheseelectronsastheymoveallowsworktobedone.

Chapter1CircuitFundamentals导体价电子层电子的运动产生电流。导体原子的外部电子叫做自由电子。当这些电子运动时释放出能量，从而做功。[10]Acircuitisapathorconductorforelectriccurrentflow.Electriccurrentflowsonlywhenithasacomplete,orclosed-circuit,path.Theremustbeasourceofelectricalenergytocausecurrenttoflowalongaclosedpath.Chapter1CircuitFundamentals电路是由于电流流通的路径或导体。只有当电路是通路或闭合的路径时才有电流流通。必须有电源来引起电流沿闭合路径流通。[11]Anelectricalenergysourcesuchasabatteryorgeneratorproducescurrentflowthroughacircuit.Asvoltageisincreased,theamountofcurrentinthecircuitisalsoincreased.Voltageisalsocalledelectromotiveforce(EMF).Chapter1CircuitFundamentals电能源，如电池或发电机，产生流过电路的电流。当电压增加时，电路中电流的数值也增加。电压也称为电动势。[12]Atomsofsomematerialsgiveuptheirfreeelectronseasily.Thesematerialsofferlowoppositiontocurrentflow.Othermaterialsholdtheirouterelectronsandofferhighoppositiontocurrentflow.一些材料的原子容易释放它们的自由电子。这些材料对流通电流的阻力小。而其它材料束缚它们的外层电子，对流通电流的阻力大。Chapter1CircuitFundamentals[13]Currentismeasuredbyconnectingthemeterintoacircuit,i.e.connectingthemeterinserieswiththecircuit.Currentflowsfromavoltagesourcewhensomedevicethathasresistanceisconnectedtothesource.测量电流时需把仪表接入电路中，即仪表与电路相串联。当某个有阻值的器件与电源相连时就会从电压源产生电流。Chapter1CircuitFundamentals[14]Therearethreetypesofelectricalcircuits.Theyarecalledseriescircuits,parallelcircuits,andcombinationcircuits.Theeasiesttypeofcircuittounderstandistheseriescircuit.电路可分为三种类型。分别为串连电路，并联电路和串并联组合电路。串连电路是最容易理解的电路类型。Chapter1CircuitFundamentals[15]Forexample,themostimportantACvalueiscalledtheeffective,ormeasured,value.Thisvalueislessthanthepeakpositivevalue.AcommonACvoltageis220V,whichisusedinhomes.Thisisaneffectivevaluevoltage.Itspeakvalueisabout311V.例如，最重要的交流值叫做有效值或测量值。这个值比正向峰值小。通常应用于我们家庭的交流电压为220伏，这个电压是有效值电压。它的峰值电压大约是311伏。Chapter1CircuitFundamentals[16]Thetermphasereferstotime,orthedifferencebetweenonepointandanother.Iftwosine-wavevoltagesreachtheirzeroandmaximumvaluesatthesametime,theyareinphase.术语“相位”指的是时间上或两点之间的不同。如果两个正弦波电压在同一时刻到达它们的零点和最大值，就说它们是同相位的。Chapter1CircuitFundamentals[17]Three-phaseACisusedtopowerlargeequipmentinindustryandcommercialbuildings.Itisnotdistributedtohomes.Therearethreepowerlinesonathree-phasesystem.Somethree-phasesystemshaveaneutralconnectionandothersdonot.在大功率工业设备和商业建筑上使用三相交流。三相交流电不配送给家庭。三相系统有三条动力线。其中一些三相系统有中性线，而其它的没有中性线。Chapter1CircuitFundamentals[18]Thepowerratingsofmotorsandgeneratorsisgreaterwhenthree-phaseacpowerisused.Foracertainframesize,theratingofathree-phaseacmotorisalmost50%largerthanasimilarsingle-phaseacmotor.

当使用三相交流电源时，电动机和发电机的功率额定值要大得多。