电子与通信技术专业英语 第6版 课件 6版 Project 4 The Transistor and Its Basic Circuit

电子与通信技术专业英语电子信息工程学院Project4

TheTransistorandItsBasicCircuit

TheTransistorandItsBasicCircuitTransistorsarethemostimportantdeviceinelectronicstoday.Notonlyaretheymadeasdiscrete(separate)componentsbutintegratedcircuits(ICs)maycontainseveralthousandonatinysliceofsilicon.Transistorsarethree-terminaldevicesusedasamplifiersandasswitches.Therearetwobasictypes.Theyare:(I)thejunctiontransistor(usuallycalledthetransistor);itsoperationdependsontheflowofbothmajorityandminoritycarriersandithastwop-njunctions,and(II)thefieldeffecttransistor(calledtheFET)inwhichcurrentisduetomajoritycarriersonly(eitherelectronsorholes)andthereisjustonep-njunction.晶体管及其基本电路

目前，晶体管是电子技术中最重要的器件。它不仅作为分立元件，而且在集成电路芯片中也包含成千上万的晶体管。

晶体管是三端器件，可用于放大器和作为开关器件使用，晶体管有两种基本类型。（1）结型晶体管（通常称晶体管）。它的工作依赖于两种载流子即多数载流子和少数载流子的流动，并且有两个PN结。（2）场效应晶体管（简称场效应管）。它的电流仅由多数载流子提供（可以是电子，也可以是空穴）且只有一个PN结。Atransistorconsistsofthreelayersofsemiconductormaterial:athinlayerofonetypewiththeothertypeoneachside.Therearetwopossiblearrangements:n-typeinthemiddlewithp-typeoneachside(PNP)andp-typeinthemiddlewithn-typeoneachside(NPN).Thecenteriscalledbase,oneoutsidelayeriscalledtheemitter,andtheotherisknownasthecollector(asshowninFig.4-1).Fig.4-1p-njunctionandtransistor

晶体管由三层半导体材料构成：薄层类型的在中间，两边分别安排另一种类型的材料。可以有两种放置方法：N型在中间，P型在两边（PNP）；P型在中间，N型在两边（NPN）。中间称为基极，两边分别称为发射极和集电极（如图4-1所示）。图4-1Atransistorisanelectronicallydevicethatregulatesthecurrentflowingthroughit.Currentfromapowersourceenterstheemitter,passesthroughtheverythinbaseregion,andleavesviathecollector.Currentflowisalwaysinthisdirection.Thiscurrentcanbemadetovaryinamplitudebyvaryingthecurrentflowinginthebasecircuit.Ittakesonlyasmallchangeofbasecurrenttocontrolarelativelylargecollectorcurrent.Itisthisabilitythatenablesthetransistortoamplify.

晶体管是调节流过它的电流的电子控制器件，电流从电源流进发射极，穿过很薄的基区，再从集电极流出，电流始终朝着这个方向流动。改变基极电流，这个电流的大小也会改变，基极电流只需很小的变化，就会引起集电极电流很大的变化。正是这种能力使晶体管能起放大作用。Therearethreebasicwaysofconnectingtransistorsinacircuit（asshowninFig.4-2）:common-base,common-emitter,andcommon-collector.Inthecommon-baseconnection,thesignalisintroducedintotheemitter-basecircuitandextractedfromthecollector-basecircuit.Becausetheinputoremitter-basecircuithasalowimpedanceintheorderof0.5to50ohms,andtheoutputorcollectorbasecircuithasahighimpedanceintheorderof1000ohmstoonemegeohm,thevoltageorpowergain

inthistypeofconfigurationmaybeintheorderof1500.Fig.4-2Threebasicwaysofconnectingtransistorsinacircuit

晶体管在电路中有三种连接方式（如图4-2所示）：共基极、共发射极和共集电极。在共基极连接中，信号从基-射回路输入，从集-射回路输出。因为基-射回路的输入阻抗较低，约为0.5到50欧姆，而集-射回路的输出阻抗较高，约为1000欧姆到1兆欧，因此，这种结构的电路的电压或功率增益可达1500倍。Inthecommon-emitterconnection,thesignalisintroducedintothebase-emittercircuitandextractedfromthecollector-emittercircuit.Thisconfigurationhasmoremoderateinputandoutputimpedancethanthecommon-basecircuit.Theinput(base-emitter)impedanceisintherangeof20to5000ohms,andoutput(collector-emitter)impedanceisabout50to50,000ohms.Powergainsintheorderof10,000(orabout40db)canberealizedwiththiscircuitbecauseitprovidesbothcurrentgainandvoltagegain.

在共发射极连接中，信号从基-射回路输入，从集-射回路输出，与共基极组态相比，这种结构有中等的输入和输出阻抗，输入电阻约为20到5000欧姆，输出电阻约为50到50000欧姆。由于既有电压增益又有电流增益，这种结构的功率增益可达10000倍（大约40db）。Thethirdtypeofconnectionisthecommon-collectorcircuit.Inthisconfiguration,thesignalisintroducedintothebase-collectorcircuitandextractedfromtheemitter-collectorcircuit.Becausetheinputimpedanceofthetransistorishighandtheoutputimpedancelowinthisconnection,thevoltagegainislessthanoneandthepowergainisusuallylowerthanthatobtainedinacommon-baseoracommon-emittercircuit.

第三种连接方式是共集电极连接。在这种结构中，信号从基-集回路输入，从射-集回路输出。由于晶体管的输入阻抗高而输出阻抗低，其电路的电压增益小于1，其功率增益比共发射极和共基极电路低。

谢谢！电子与通信技术专业英语电子信息工程学院Project4

TheTransistorandItsBasicCircuitNotes1.Therearetwopossiblearrangements:n-typeinthemiddlewithp-typeoneachside(PNP)andp-typeinthemiddlewithn-typeoneachside(NPN).译文：可以有两种安排：n型在中间，p型在两边（PNP）；p型在中间，n型在两边（NPN）。n-type…oneachside(PNP)和p-type…oneachside(NPN)是arrangements的同位语。2.…oneoutsidelayeriscalledtheemitter,andtheotherisknownasthecollector.译文：……中间称为基极，两边分别称为发射极和集电极。one…theother…是一个常见的句型：“一个…...另一个”。3.Ittakesonlyasmallchangeofbasecurrenttocontrolarelativelylargecollectorcurrent.译文：基极电流只需很小的变化，就会引起集电极电流很大的变化。重要句型Ittakes…todosth.：指花费多少时间（金钱等）来做谋事。4.Itisthisabilitythatenablesthetransistortoamplify.译文：

正是这种能力使晶体管能起放大作用。此句是强调句型，强调thisability．5.…common-base,common-emitter,andcommon-collector.译文:……共基极、共发射极、共集电极。此为同位语。6.…andthepowergainisusuallylowerthanthatobtainedinacommon-baseoracommon-emittercircuit.

译文:……并且功率增益比共发射极和共基极电路低。that指代thepowergain；(2)obtainedinacommon-baseoracommon-emittercircuit是过去分词短语，后置定语，修饰that．

谢谢！电子与通信技术专业英语电子信息工程学院Project4

TheTransistorandItsBasicCircuitNewwordsandphrasesNewwordsoperation[ɒ,pə’reIən]n.运算，操作，经营，手术base[beɪs]n.基极emitter[ɪ’mɪtə]n.发射极collecto[kə’lektə]rn.集电极forward[’fɔːwəd]ad.正向bias[’baɪəs]v.&n.偏置；偏见reverse[rɪ’vɜːs]v.&n.

反向；背面，反面

Newwordsextract[’ekstrækt]

v.输出impedance[ɪm’piːdns]

n.阻抗gain[geɪn]

n.

增益configuration

[kən,fɪɡə’reɪʃn]

n.结构moderate[’mɒd(ə)rət]

a.适度的obtain[əb’teɪn]

v.获得discrete[di'skri:t]adj.不连续的，离散的

PhrasesandExpressionsfieldeffecttransistor场效应晶体管thinlayer薄层intheorderof

约为，大约

intherangeof

在……范围内

toconsistof

由……组成

PhrasesandExpressionspowergain功率增益；功率放大系数common-emittercircuit共发射极电路common-collectorcircuit共集电极电路base-collectorcircuit共基极电路inputimpedance输入阻抗谢谢！电子与通信技术专业英语电子信息工程学院Project4

TransistorVoltageAmplifierExercises1.WriteT(True)orF(False)besidethefollowingstatementsaboutthetext.a.Atransistorconsistsofthreelayersofsemiconductormaterial:athinlayerofonetypewiththeothertypeoneachside.b.Thecenterisbase,oneoutsidelayeristhecollector,andtheotheristheemitter.c.Currententerstheemitter,passesthroughthebase,andleavesviathecollector.d.Currentflowisalwayschangedirections.e.Ittakesagreatchangeofbasecurrenttocontrolarelativelylargecollectorcurrent.Itisthisabilitythatenablesthetransistortoamplify.f.Inthecommon-baseconnection,thesignalisintroducedintothecollector-basecircuitandextractedfromtheemitter-basecircuit.g.Inthecommon-emitterconnection,thesignalisintroducedintothebase-emittercircuitandextractedfromthecollector-emittercircuit.h.Thecommon-emitterconnectionhasmoremoderateinputandoutputimpedancethanthecommon-basecircuit.a.Therearetwopossiblearrangements:________inthemiddlewithp-typeoneachside(PNP)and________inthemiddlewithn-typeoneachside(NPN).

b.Becausetheinputoremitter-basecircuithasa_____impedanceintheorderof0.5to50ohms,and