资源描述：
《A 运算放大器-自动化专业外文翻译》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、UNIT2A:TheOperationalAmplifierOneproblemwithelectronicdevicescorrespondingtothegeneralizedamplifiersisthatthegains,AuorA~,dependuponinternalpropertiesofthetwo-portsystem(p,fl,R~,Ro,etc.)?~Thismakesdesigndifficultsincetheseparametersusuallyvaryfromdevic
2、etodevice,aswellaswithtemperature.Theoperationalamplifier,orOp-Amp,isdesignedtominimizethisdependenceandtomaximizetheeaseofdesign.AnOp-Ampisanintegratedcircuitthathasmanycomponentpartsuchasresistorsandtransistorsbuiltintothedevice.Atthispointwewillmake
3、noattempttodescribetheseinnerworkings.AtotallygeneralanalysisoftheOp-Ampisbeyondthescopeofsometexts.Wewillinsteadstudyoneexampleindetail,thenpresentthetwoOp-Amplawsandshowhowtheycanbeusedforanalysisinmanypracticalcircuitapplications.Thesetwoprinciplesa
4、llowonetodesignmanycircuitswithoutadetailedunderstandingofthedevicephysics.Hence,Op-Ampsarequiteusefulforresearchersinavarietyoftechnicalfieldswhoneedtobuildsimpleamplifiersbutdonotwanttodesignatthetransistorlevel.Inthetextsofelectricalcircuitsandelect
5、ronicstheywillalsoshowhowtobuildsimplefiltercircuitsusingOp-Amps.Thetransistoramplifiers,whicharethebuildingblocksfromwhichOp-Ampintegratedcircuitsareconstructed,willbediscussed.ThesymbolusedforanidealOp-AmpisshowninFig.1-2A-1.Onlythreeconnectionsaresh
6、own:thepositiveandnegativeinputs,andtheoutput.NotshownareotherconnectionsnecessarytoruntheOp-Ampsuchasitsattachmentstopowersuppliesandtogroundpotential.ThelatterconnectionsarenecessarytousetheOp-Ampinapracticalcircuitbutarenotnecessarywhenconsideringth
7、eideal0p-Ampapplicationswestudyinthischapter.ThevoltagesatthetwoinputsandtheoutputwillberepresentedbythesymbolsU+,U-,andUo.Eachismeasuredwithrespectt~groundpotential.Operationalamplifiersaredifferentialdevices.Bythiswemeanthattheoutputvoltagewithrespec
8、ttogroundisgivenbytheexpressionUo=A(U+-U-)(1-2A-l)whereAisthegainoftheOp-AmpandU+andU-thevoltagesatinputs.Inotherwords,theoutputvoltageisAtimesthedifferenceinpotentialbetweenthetwoinputs.Integratedcircuittechnologyallowsconstructionofma
