电子信息技术专业英语-教学 Unit-4

Unit

4

Operational

Amplifier1运算放大器一.NEWWORDS21.amplifier

[΄æmpli͵faiə

]

n.放大器，扩音器2.analogue

[΄ænəlɔɡ]n.模拟

adj.模拟的3.variety

[və΄raiəti

]

n.变化,多样性,种类4.discrete

[

dis΄kri:t]adj.不连续的,

离散的5.internal

[in΄tə:nl

]

adj.内在的,

国内的6.denote

[di΄nəut

]vt.指示,

表示7.invert

[in΄və:t

]vt.使颠倒,

使转化8.available

[ə΄veiləbl

]adj.可获得的9.package

[΄pækiʤ

]n.包裹,包,管壳• 10.pin

[pin

]n.钉,管脚，引线11.impedance

[im΄pi:dəns

]n.[电]阻抗，阻抗1.operational

amplifier 运算放大器•••3invertinginputnon-invertinginput8pindual-in-line反向输入端同向输入端8管脚双列直插式二.Technicalterms:三.

Expressions:4avariety

ofeventhoughbeinterested

inbeknownaswithrespecttobeequalto各种各样的即使对...感兴趣被称为…关于,至于等于，与…相等四.

Questions

for

text

discussion:51.Whyisoperational

amplifier

giventhename?2.Drawthecircuit

symbolofanoperational

amplifier.3.Talkabouttheapplication

oftheoperational

amplifier.The

first

paragraph: Theoperational

amplifier

isthemostimportantbasic

blockofalllinear

circuits.

Ithas

awiderangeapplications

insuch

fieldsasanalogue

signaloperations,amplification,

filtering,

waveformsproducing,linear

andnon-linearsignalshanding,etc.译：运算放大器是所有线性电路中最重要的基本器件。它的应用十分广泛，包括模拟信号的运算，放大，滤波，波形发生器，以及进行线性和非线性信号的处理等。6五

Learnthetext:Thesecondparagraph:Theterm

“operational

amplifier”

wasoriginally

applied

tohighgainamplifiers

operatingdowntozerofrequencywhichwereusedinanalogue

computerstoperformcertain

mathematicaloperations.Thesehighgainamplifier

arenowusedfor

awidevariety

ofapplications,

butthename

“operational

amplifiers”

or“op-amp”

isnormallyuseeventhoughnomathematical

operationareinvolved.

Theearlyoperational

amplifieremployed

discretecomponents,

butitisnowmuchmoreconvenient

toemployanintegrated

circuit.

Thecircuit

designersisnotgenerally

interestedintheinternal

components

ofanintegrated

circuit,

butonly

intheperformance

oftheunitas

awhole.Therefore,thesymbolinFig.2isusedtodenote

theamplifier.

Itcan

beseen

that

there

aretwoinputs,oneoutputandconnection

thepositive

andnegativesupplylines.7注：这里

whichwere used…mathematical

operational

为定语从句，修饰前面的 highgainamplifiers,

因为定语从句并未直接跟在所修饰的先行次后，语法上称其为分割定语。而定语从句中的

toperformcertain

mathematical

operations

为动词不定式短语，作目的状语。8•

译：运算放大器这一术语最早适用于下限频率可低到零赫兹的高增益放大器，它可用于模拟计算机中执行某些数学运算。这种高增益的放大器现在已被广泛应用于各个方面，早已远远超出数值运算的范围，但通常仍称之为运算放大器或OP-

AMP。早期的运算放大器适用分立元件，但现在适用集成电路就更为方便了。电路设计者通常对集成电路内波元件并不感兴趣，只关心作为一个整体的单元性能。因此，图2所示的符号用来表示运算放大器。由图可见，运放有两个输入端，一个输出端以及正、负电源端子。9Thethird

paragraph:10Iftheinvertinginputismadeslightlymorepositive,

theoutputwillbecome

morenegative,

thisiswhythename“inverting”

isgiventothisinput.if,thenon-invertinginputismade

morepositive,theoutputwillalsobecomemorepositive.译：如果反向输入端正电压略微增加一点，那么输出负电压变得更强，这就是为什么称这个输入端为“反向输入端” 的原因。然而，如果同相收入电压正向增大，输出端正电压也将变得更强。11Thefourth

paragraph:Type741device

isoneofthebestknowngeneralpurposeoperational

amplifier

andisalsooneofthecheapest

ofall

linear

integrated

circuits.

Thedevice

isactually

available

in

anumberofdifferentpackages.Readerswillusuallyfindthetypeof741showninFig.3.Thistypeofpackage

isknownasthe8pindual-in-line.译：741型器件是众所周知的通用运算放大器之一，也是所有的线性集成电路中最便宜的一种。这种器件实际上具有不同的封装形式。读者通常会发现如图3所示的741型器件最便于使用，这种封装形式为8管脚双列直插式11Thefifthparagraph:12Abasic

circuit

ofa741inverting

amplifierisshowninFig.4.Theinputsignalisfedtothe

invertinginputof741viaR1andthereforetheoutputisinverted

inphaserespect

totheinput.Operational

amplifier

aredesignedtohave

averyhighinputimpedance.

Theinputcurrentsofthe741circuit

arethereforeverysmall.Astheinvertinginputisvirtually

atgroundpotential,thecurrentwhichflowsthroughR1

isequal

totheinputvoltageUi

dividedbyR1.Similarly,

thecurrentflowingthrough

R3

is–Uo/R3.where

Uo

istheoutputvoltage.

Thesetwocurrentarealmostequal,

thusthevoltage

gainofcircuit

isequal

totheresistorvalues

G=

-R3/R1.•

译 : 741反向放大器的基本电路如图4所示。输入信号经R1加在741器件的反相输入端，因此输出信号与输入信号的相位相反。运算放大器设计成具有很高的输入阻抗，因此741的净输入电流非常小。由于反相输入端虚短，流过R1的电流等于Ui除以R3，同样流过R3的电流等于-Uo/R3，其中Uo输出电压。这两个电流几乎相等，因此电路的电压增益取决于电阻值：G

=

-R3/R11314Dotheexercises:1.Translate

thefollowing

phrasesandexpressions.• (1)运算放大器•(2)to

benot

generally

interested

intheinternal

components

ofanintegratedcircuit• (3)正、负电源端• (4)8管脚双列直插式集成块(5)to

bevirtually

atground

potential5.Translate

thefollowing

sentencesinto

English.• (1)运算放大器是一种高增益的放大器。• (2)741器件是最常用也是最便宜的集成电路之一。• (3)将输入信号加到运放的同相输入端。Answer:Op-ampis

akind

ofhigh

gain

amplifier.Type741is

oneofthemost

commonly

used,andthecheapestIC.Applythe

input

signal

tothe

non-inverting

inputof

op-amp.14Reading:OscillatorTranslatethisparagraphintoChinese: Aunitthatgenerates（产生）

asignaliscalledanoscillator（振荡器）.OscillatorsareusedtoprovideACsignalsfromfrequencies（频率）

justabovezero

tofrequencies

inthegigahertz（千兆赫）

regionatthetopendoftheradio-frequencypartoftheelectromagnetic

spectrum（电磁波谱）.

Theymaybedescribedinoneoftwowaysintermsofthetypeofsignalwaveformgenerated:sinusoidal

oscillators

and

relaxationoscillators（张弛振荡器）.

Asinusoidal

oscillator

generatesasignalhavingasinewaveform;arelaxationoscillatorgeneratesasignalthatisusuallyofsquarewaveform.15Dialogue:Amplifier

Design16Supervisor:

Iwouldlikeyoutodo

apreliminary

calculation

foranamplifier.Engineer:

Whatarethedetails?

Howistheamplifier

tobeused?••Supervisor:Itmustgiveavoltagegainofabout1000.Engineer:

Thatisn’tenoughinformation.

Ineedtoknowthedesiredinputimpedanceaswellasthetypesofloadstobeusedwiththeamplifier.Supervisor:Itmusthave

ahighinputimpedance

withaninputcapacitance

ofno