电气工程及其自动化专业英语第一章课文翻译.docx

电气工程及其自动化专业英语第一章课文翻译

第一篇：电气工程及其自动化专业英语第一章课文翻译第一章第一篇sectiongTwovariablesu(t)andi(t)arethemostbasicconceptsinanelectriccircuit,theycharacterizethevariousrelationshipsinanelectriccircuitu(t)和i(t)这两个变量是电路中最基本的两个变量，它们刻划了电路的各种关系。ChargeandCurrentTheconceptofelectricchargeistheunderlyingprincipleforexplainingallelectricalphenomena.Also,themostbasicquantityinanelectriccircuitistheelectriccharge.Chargeisanelectricalpropertyoftheatomicparticlesofwhichmatterconsists,measuredincoulombs(C).电荷和电流电荷的概念是用来解释所有电气现象的基本概念。也即，电路中最基本的量是电荷。电荷是构成物质的原子微粒的电气属性，它是以库仑为单位来度量的。Weknowfromelementaryphysicsthatallmatterismadeoffundamentalbuildingblocksknownasatomsandthateachatomconsistsofelectrons,protons,andneutrons.Wealsoknowthatthechargeeonanelectronisnegativeandequalinmagnitudeto1.60210×1019C,whileaprotoncarriesapositivechargeofthesamemagnitudeastheelectron.Thepresenceofequalnumbersofprotonsandelectronsleavesanatomneutrallycharged.我们从基础物理得知一切物质是由被称为原子的基本构造部分组成的，并且每个原子是由电子，质子和中子组成的。我们还知道电子的电量是负的并且在数值上等于1.602100×10-12C，而质子所带的正电量在数值上与电子相等。质子和电子数量相同使得原子呈现电中性。Weconsidertheflowofelectriccharges.Auniquefeatureofelectricchargeorelectricityisthefactthatitismobile;thatis,itcanbetransferredfromoneplacetoanother,whereitcanbeconvertedtoanotherformofenergy让我们来考虑一下电荷的流动。电荷或电的特性是其运动的特性，也就是，它可以从一个地方被移送到另一个地方，在此它可以被转换成另外一种形式的能量。Whenaconductingwireisconnectedtoabattery(asourceofelectromotiveforce),thechargesarecompelledtomove;positivechargesmoveinonedirectionwhilenegativechargesmoveintheoppositedirection.Thismotionofchargescreateselectriccurrent.Itisconventionaltotakethecurrentflowasthemovementofpositivecharges,thatis,oppositetotheflowofnegativecharges,asFig.l-1illustrates.ThisconventionwasintroducedbyBenjaminFranklin(l706～l790),theAmericanscientistandinventor.Althoughwenowknowthatcurrentinmetallicconductorsisduetonegativelychargedelectrons,wewillfollowtheuniversallyacceptedconventionthatcurrentisthenetflowofpositivecharges.Thus,Electriccurrentisthetimerateofcharge,measuredinamperes(A).Mathematically,therelatio