上海海事学院信息工程学院

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1、上海海事大学信息工程学院Unit3CircuitAnalysisUsingtheIdealOperationalAmplifierBackgroundWordsandexpressionsTextandnotesGrammarExercisesReadingmaterial上海海事大学信息工程学院BackgroundAnamplifier,electronicamplifieror(informally)ampisanelectronicdevicethatincreasesthepowerofasignal.Itdoesthisbytakingenergyfromapowersupplyan

2、dcontrollingtheoutputtomatchtheinputsignalshapebutwithalargeramplitude.Inthissense,anamplifiermodulatestheoutputofthepowersupplytomaketheoutputsignalstrongerthantheinputsignal.Anamplifieriseffectivelytheoppositeofanattenuator:whileanamplifierprovidesgain,anattenuatorprovidesloss.上海海事大学信息工程学院Backgrou

3、ndThetypesofamplifierscanbecategorizedindifferentways.Oneisbythefrequencyoftheelectronicsignalbeingamplified;audioamplifiersamplifysignalsintheaudio(sound)rangeoflessthan20 kHz,RFamplifiersamplifyfrequenciesintheradiofrequencyrangebetween20 kHzand300 GHz.Anotheriswhichquantity,voltageorcurrentisbein

4、gamplified;amplifierscanbedividedintovoltageamplifiers,currentamplifiers,transconductance(跨导)amplifiers,andtransresistanceamplifiers.Afurtherdistinctioniswhethertheoutputisalinearornonlinearrepresentationoftheinput.Amplifierscanalsobecategorizedbytheirphysicalplacementinthesignalchain（信号通路，信号链）.Thef

5、irstpracticalelectronicdevicewhichcouldamplifywastheAudion(triode，三极管)vacuumtube,inventedin1906byLeeDeForest,whichledtothefirstamplifiers.Theterms"amplifier"and"amplification"(fromtheLatinamplificare,'toenlargeorexpand')werefirstusedforthisnewcapabilityaround1915whentriodesbecamewidespread.[2]Forthe

6、next50yearsvacuumtubesweretheonlydeviceswhichcouldamplify,andwereusedinallamplifiersuntilthe1960s,whentransistorsbegantobeused.Mostamplifierstodayusetransistors,althoughtubesarestillused.上海海事大学信息工程学院上海海事大学信息工程学院WordsandexpressionsBuffern.缓冲器By-productn.副产品，出乎意料的结果Circuitryn.电路，线路Formulan.公式，规则Fulcru

7、mn.杠杆的支点Groundv.使接地；n.接地，地线Impedancen.阻抗Infinitesimaladv.无穷小，极小，无限小Inherentadj.固有的，内在的，与生俱来的Intuitiveadj.直觉的Investigatev.调查，研究Latchv.闭锁(n.锁存器)Levern.杆，杠杆Mythicaladj.神话的，虚构的Offsetn.偏移量，抵消上海海事大学信息工程学院Wo