1、刘 骋 蔡 静 刘小芹 主编电子与通信技术专业英语（第5版）高职高专电子信息类“十三五”规划教材English on Electronic and Telecommunication Technology01Unit Unit Basic Knowledge of ElectronicsLesson 4 Lesson 4 Transistor Voltage Amplifier Unit Unit New WordsNew Wordsoscilloscope siluskup n.示波器alternating:lt,neiti a.交互的amplifier mplifai n.放大器junct
2、ion dkn n.连接,接合,交叉点,汇合处resistor rizist n.电阻器quiescentkwaiesnt a.静止的New WordsNew Wordsbiased baist a.结果偏倚的,有偏的silicon silikn n.硅,硅元素superimpose,sju:primpuz v.添加,双重Proportionateprup:nit a.&v.成比例的，成比例equation ikwein n.方程式,等式Phrases and ExpressionsPhrases and Expressionsto convertinto 把转变成as a result 结果
3、Amplifiers are necessary in many types of electronic equipment such as radios,oscilloscopes and record players.Often it is a small alternating voltage that has to be amplified.A junction transistor in the common-emitter mode can act as a voltage amplifier if a suitable resistor,called the load,is co
4、nnected in the collector circuit.Lesson 4 Transistor Voltage AmplifierChinese Translation of TextsChinese Translation of Texts放大器广泛用于各种电子设备，如收音机、示波器、录音机等，因为常有小的交流电压需要放大。一个结型晶体管连成共发组态，在其集电极回路中接入合适的电阻，称为负载，则可构成电压放大器。第 4 课 晶体管电压放大器Chinese Translation of TextsChinese Translation of TextsThe small altern
5、ating voltage,the input ui,is applied to the base-emitter circuit and causes small changes of base current which produce large changes in the collector current flowing through the load.The load converts these current changes into voltage changes which form the alternating output voltage uo(uo being
6、much greater than ui).Chinese Translation of TextsChinese Translation of Texts一个小的交流输入电压ui，加在基-射回路中，产生小的基极交变电流进而产生一个大的集电极交变电流流过负载，负载将交变电流转变成交变电压即为输出交流电压uo(uo比ui大)。Chinese Translation of TextsChinese Translation of Texts A transistor voltage amplifier circuit is shown in Fig.4-1.To see just the volta
7、ge amplification occurs,consider first the situation when there is no input,i.e.ui=0,called the quiescent(quiet)state.Chinese Translation of TextsChinese Translation of Texts 一个简单的电路如图4-1所示，表明了电压放大的过程，首先考虑没有输入电流，即ui=0的情形，称为静态。Chinese Translation of TextsChinese Translation of Texts For transistor ac
8、tion to take place the base-emitter junction must always be forward biased.A simple way of ensuring this is to connect a resistor RB,called the base-bias resistor.A steady(D.C.)base current IB flows from battery+,through RB into the base and back to battery-,via the emitter.The value of RB can be ca
9、lculated once the value of IB for the best amplifier performance has been decided.Chinese Translation of TextsChinese Translation of TextsChinese Translation of TextsChinese Translation of Texts 晶体管工作在放大状态时其发射结必须为正向偏置。为保证发射结正偏，简单的方法是接一个电阻RB，称为基极偏置电阻。基极偏置电流IB从电源正极流出，经RB流入基极；再经发射极流回电源负极。一旦IB在放大器的最佳状态下
10、确定后，可以随之计算出RB的值。If VCC is the battery voltage and VBE is the base-emitter junction voltage(always about+0.6V for an n-p-n silicon transistor),then for the base-emitter circuit,since D.C.voltages add up,we can write VCC=IB RB+VBE (1)Chinese Translation of TextsChinese Translation of Texts 如果VCC为电源电压，
11、VBE为发射结电压（NPN硅管为0.6V），则对基极回路，若加有交流电压，有 VCC=IB RB+VBE (1)Chinese Translation of TextsChinese Translation of Texts IB causes a much larger collector current IC which produces a voltage drop ICRL across the load RL.If VCE is the collector-emitter voltage,then for the collector-emitter circuit VCC=ICRL+
12、VCE (2)Chinese Translation of TextsChinese Translation of Texts IB产生了一个相当大的集电极电流IC，其在负载RL上产生电压降IC RL。若VCE为集电结电压，则对集电极回路，有 VCC=IC RL+VCE (2)Chinese Translation of TextsChinese Translation of Texts When ui is applied and goes positive it increases the base-emitter voltage slightly(e.g.from+0.60 V to+0
13、.61 V).When ui swings negative,the base-emitter voltage decreases slightly(e.g.from+0.60V to+0.59V).As a result a small alternating current is superimposed on the quiescent base current IB which in effect becomes a varying D.C.Chinese Translation of TextsChinese Translation of Texts 当交流电压ui加入且为正时，基极
14、电压略有增加（如从0.60V到0.61V）；当ui为负时，基极电压略有下降（如从0.60V到0.59V）。结果是一个小的交流电流叠加在静态基极电流IB上并产生一个变化的交流电压。Chinese Translation of TextsChinese Translation of Texts When the base current increases,large proportionate increases occur in the collector current.From equation(2)it follows that there is a corresponding larg
15、e decrease in the collector-emitter voltage(since Vcc is fixed).A decrease of base current causes a large increase of collector-emitter voltage.In practice positive and negative swings of a few milli-volts in Ui,can result in a fall or rise of several volts in the voltage across RL and so also in th
16、e collector-emitter voltage.Chinese Translation of TextsChinese Translation of Texts 当基极电流增大，集电极电流大幅增大。由式（2）可知，将相应引起集射间电压大幅下降（因为VCC一定）。同理，基极电流减小将引起集射间电压大幅增加。即Ui在正负间有微伏数量级的摆动，就会导致负载RL上的电压及集射间电压有较大的幅值变化。Chinese Translation of TextsChinese Translation of Texts The collector-emitter voltage may be regar
17、ded as an alternating voltage superimposed on a steady direct voltage,i.e.on the quiescent value of VCE.Only the alternating part is wanted and capacitor C blocks the direct part but allows the alternating part,i.e.the output uo to pass.Chinese Translation of TextsChinese Translation of Texts 集射间电压可
18、以认为是一个交流电压叠加在静态直流电压（即静态电压VCE）之上，若只需交流部分，则可利用电容器C的隔直流作用，将直流部分去掉，只允许交流电压uo通过。Chinese Translation of TextsChinese Translation of TextsNotesNotesOften it is a small alternating voltage that has to be amplified.通常小的交流电压需要放大。这是一个常见句型，it是形式主语，that has to be amplified引导真正意义上的主语从句。1NotesNoteswhich produce la
19、rge changes in the collector current flowing through the load.(1)which引出base current；(2)flowing through the load是现在分词 短 语，充 当 后 置 定 语，修 饰collector current2NotesNotesThe load converts these current changes into voltage changes which form the alternating output voltage uo(uo being much greater than ui
20、).负载将交变电流转变成交变电压即为输出交流电压uo(uo比ui大)。(1)to convert into：把 变成,相当于to change into;(2)which form the alternating output voltage uo是定语从句，修饰voltage changes;(3)alternating是现在分词短语，修饰output voltage。3NotesNotesA simple way of ensuring this is to connect a resistor RB,called the base-bias resistor,as shown.简单的方法
21、是接一个电阻RB，称为基极偏置电阻。不定式to connect a resistor RB充当表语，其中called the base-bias resistor是过去分词短语，充当定语；as shown其义为“如图所示”。4NotesNotesAs a result a sma1l alternating current is superimposed on the quiescent base current IB which in effect becomes a varying d.c.结果是一个小的交流电流叠加在静态基极电流IB上并产生一个变化的交流电压。(1)as a result
22、：“结果”；（2）which in effect becomes a varying d.c.是定语从句，修饰the quiescent base current IB5NotesNotes and so also in the col1ector-emitter voltage.so这里指can also result in a fall or rise of several volts.6NotesNotesThe collector-emitter voltage may be regarded as an alternating voltage superimposed on a st
23、eady direct voltage,i.e.on the quiescent value of VCE.集-射间电压可以认为是一个交流电压叠加在静态直流电压（即静态电压VCE）之上。过去分词短语superimposed on a steady direct voltage,i.e.on the quiescent value of VCE充当定语，修饰an alternating voltage7ExercisesExercises 1.Write T(True)or F(False)beside the following statements about the text.a.Ampl
24、ifiers are necessary in many types of electronic equipment such as radios,oscilloscopes and record players.Often it is a large alternating current that has to be amplified.b.A junction transistor in the common-emitter mode can act as a resistance amplifier.c.The small alternating voltage is applied
25、to the base-emitter circuit and causes large changes of base current which produce small changes in the collector current flowing through the load.d.The load converts current changes into voltage changes,which form the alternating output voltage.ExercisesExercises 1.Write T(True)or F(False)beside th
26、e following statements about the text.e.For transistor action to take place the base-emitter junction must always be forward straight line.f.When the base current increases,large proportionate increases occur in the collector current.g.A decrease of base current causes a large increase of collector-
27、emitter voltage.h.The collector-emitter voltage may be regarded as an alternating voltage superimposed on a steady direct voltage.ExercisesExercises 1.Write T(True)or F(False)beside the following statements about the text.a.Amplifiers are necessary in many types of electronic equipment such as radio
28、s,oscilloscopes and record players.Often it is a large alternating current that has to be amplified.b.A junction transistor in the common-emitter mode can act as a resistance amplifier.c.The small alternating voltage is applied to the base-emitter circuit and causes large changes of base current whi
29、ch produce small changes in the collector current flowing through the load.d.The load converts current changes into voltage changes,which form the alternating output voltage.F FFTExercisesExercises 1.Write T(True)or F(False)beside the following statements about the text.e.For transistor action to ta
30、ke place the base-emitter junction must always be forward straight line.f.When the base current increases,large proportionate increases occur in the collector current.g.A decrease of base current causes a large increase of collector-emitter voltage.h.The collector-emitter voltage may be regarded as
31、an alternating voltage superimposed on a steady direct voltage.FTT（L33）TExercisesExercises2.Match the following terms to appropriate definition or expression.a.loadb.VCCc.uBEd.uoe.ui1.a suitable resistor2.the alternating output voltage3.base-emitter junction voltage4.the base-bias resistor5.battery
32、voltagef.RB6.the small alternating voltage,the inputExercisesExercises2.Match the following terms to appropriate definition or expression.a.loadb.VCCc.uBEd.uoe.ui1.a suitable resistor2.the alternating output voltage3.base-emitter junction voltage4.the base-bias resistor5.battery voltagef.RB6.the sma
33、ll alternating voltage,the inputExercisesExercises3.Fill in the missing words according to the text.a.A junction transistor in the common-emitter mode can act as a if a suitable resistor called the ,is connected in the collector circuit.b.The load converts these changes into changes,which form the a
34、lternating output voltage uo.c.A simple way of ensuring this is to connect a resistor RB,called the .A steady(DC)base current IB flows from battery“+”,through RB into the base and back to battery“”,via the .d.The collector-emitter voltage may be regarded as an superimposed on a steady direct voltage
35、,i.e.on the quiescent value of VCE.Only the alternating part is wanted and capacitor C blocks the direct part but allows the ,i.e.the output uo to pass.ExercisesExercises3.Fill in the missing words according to the text.a.A junction transistor in the common-emitter mode can act as a voltage amplifie
36、r if a suitable resistor called the load,is connected in the collector circuit.b.The load converts these current changes into voltage changes,which form the alternating output voltage uo.c.A simple way of ensuring this is to connect a resistor RB,called the base-bias resistor.A steady(DC)base curren
37、t IB flows from battery“+”,through RB into the base and back to battery“”,via the emitter.d.The collector-emitter voltage may be regarded as an alternating voltage superimposed on a steady direct voltage,i.e.on the quiescent value of VCE.Only the alternating part is wanted and capacitor C blocks the
38、 direct part but allows the alternating part,i.e.the output uo to pass.ExercisesExercises4.Translate the eighth paragraph into Chinese.When the base current increases,large proportionate increases occur in the collector current.From equation(2)it follows that there is a corresponding large decrease
39、in the collector-emitter voltage(since VCC is fixed).A decrease of base current causes a large increase of collector-emitter voltage.In practice positive and negative swings of a few milli-volts in ui,can result in a fall or rise of several volts in the voltage across RL and so also in the collector
40、-emitter voltage.ExercisesExercises4.Translate the eighth paragraph into Chinese.When the base current increases,large proportionate increases occur in the collector current.From equation(2)it follows that there is a corresponding large decrease in the collector-emitter voltage(since VCC is fixed).A
41、 decrease of base current causes a large increase of collector-emitter voltage.In practice positive and negative swings of a few milli-volts in ui,can result in a fall or rise of several volts in the voltage across RL and so also in the collector-emitter voltage.基极电流增大时，集电极电流会大幅增大。由式（2）可知，将相应引起集-射间电压大幅下降（因为VCC一定）。同理，基极电流减小将引起集-射间电压大幅增加，即ui在正负间有毫伏数量级的摆动，就会导致负载RL上的电压及集-射间电压有较大的幅值变化。刘 骋 蔡 静 刘小芹 主编电子与通信技术专业英语（第5版）高职高专电子信息类“十三五”规划教材English on Electronic and Telecommunication TechnologyEnd
