电子课件《电工英语(第三版)》A013750电工英语电子课件unit4.ppt

1、ELECTRICAL ENGLISH英语英语电工Unit 1 Job and WorkplaceUnit 2 Electrical Tools and MaterialsUnit 3 House WiringUnit 4 Measuring InstrumentsContents Unit 5 Motors and TransformersLesson10 Instrument ClassificationLesson 11 Using the MultimeterLesson 12 Using the OscilloscopeUnit 4 Measuring InstrumentsLesso

2、n10 Instrument ClassificationGoal Identify basic types and functions of basic measuring instrumentLook and Study DialogueReadingFurther StudyWords and Phrases Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study104Words and PhrasesA.Look up the words and phrases below in a dictionary.Fill i

3、n the blanks with both Chinese and English answers according to the pictures.contactor;electrical resistance;inductor;magnetic field;alternating current;dial1._2._3._contactor接触器electrical resistance电阻inductor电感 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study104Words and PhrasesA.Look

4、up the words and phrases below in a dictionary.Fill in the blanks with both Chinese and English answers according to the pictures.contactor;electrical resistance;inductor;magnetic field;alternating current;dial4._5._6._dial刻度盘magnetic field磁场alternating current交流电 Unit 3 Lesson 4 Look and Study Dial

5、ogue Reading Further Study4Words and PhrasesB.Look up the measuring instrument names below in a dictionary.Fill in the blanks with both Chinese and English answers according to the pictures.ohmmeterammetervoltmeterwattmeter1._ 2._ 3._ 4._10ammeter安培表voltmeter伏特表wattmeter功率表ohmmeter欧姆表 Unit 3 Lesson

6、4 Look and Study Dialogue Reading Further Study74Words and PhrasesJohn参加电机维修的实习，正尝试确定新安装的接触器不能正常工作的故障原因，并向Peter（B）求助。A:Peter,give me a hand.B:Whats the trouble with you？John.A:I wanted to make sure the new contactors werent going to overload the 24 volt transformer,so I started checking resistance o

7、f the coils with my ohmmeter.By my reading of Ohms law,I got the relationship between electromotive force and resistance.But actual current measured is like wrong value?So what am I doing wrong?10 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesJohn参加电机维修的实习，正尝试确定新安装的

8、接触器不能正常工作的故障原因，并向Peter（B）求助。B:John,What a silly mistake you made!Ohms Law in its basic form only applies to purely resistive circuits.The coil in the contactor is not a resistive circuit.It is an inductive circuit.Inductors have an additional resistance due to the flux of the magnetic field when alt

9、ernating current is applied to the coil.A:I got it.10 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesA.Choose the best answer1.What was the trouble with John?_A.The new contactors cant work.B.He doesnt know how to use ohmmeter.C.The ohmmeter cant work.D.The coils of

10、contactors cant work.2.Ohms Law in its basic form only applies to circuits.A.purely inductive;B.purely resistive;C.any;D.Low voltage3.Inductors have when alternating current is applied to the coil.A.no resistance;B.an additional resistance;C.no magnetic field;D.no electromotive force10ABB Unit 3 Les

11、son 4 Look and Study Dialogue Reading Further Study74Words and PhrasesB.Reorder the letters with your partner.LettersWordsw l a oi c l ic magnet ance resist ship relation 10relationshiplawcoilmagneticresistance Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and Phrases测量仪器的分类测量

12、仪器的分类The three basic quantities in the electrical measurement are current,voltage and power.The necessary requirements for any measuring instruments are:a)With the introduction of the instrument in the circuit,the circuit conditions should not be altered.Thus the quantity to be measured should not g

13、et affected due to the instrument used.b)The power consumed by the instruments for their operation should be as small as possible.10 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and Phrases测量仪器的分类测量仪器的分类The instrument which measures the current flowing in the circuit is calle

14、d ammeter while the instrument which measures the voltage across any two points of a circuit is called voltmeter.The instruments which are used to measure the power are called power meters or watt-meters.Electrical measuring instruments are mainly classified as:10 Unit 3 Lesson 4 Look and Study Dial

15、ogue Reading Further Study74Words and Phrases测量仪器的分类测量仪器的分类a)Indicating Instruments:These instruments make use of a dial and pointer for showing or indicating magnitude of unknown quantity.b)Recording Instruments:These instruments give a continuous record of the given electrical quantity which is be

16、ing measured over a specific period.c)Integrating instruments:These instruments measure the total quantity of electricity delivered over period of time.10 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesA.List the basic types of electrical measuring quantity and instr

17、ument.10quantityinstrument powercurrentvoltageintegrating instrumentsindicating instrumentsrecording instruments Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesB.Read the passage again and answer the questions.101.The instrument which measures the voltage across any

18、two points of a circuit is called .2.The instruments which are used to measure the power are called .3.The instrument which measures the current flowing in the circuit is called .voltmeterwatt-metersammeter Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesC.Learn the i

19、mportant grammar and phrase in the text.1.While引导由含有转折关系的两个分句构成的并列句，表示对比。The instrument which measures the current flowing in the circuit is called ammeter while the instrument which measures the voltage across any two points of a circuit is called voltmeter.测量电路电流的仪器称为安培表，而测量电路中任意两点之间电压的仪器称为伏特表。练习：

20、他出去散步了，而我却待在家里。英文：2.which引导限定性定语从句These instruments give a continuous record of the given electrical quantity which is being measured over a specific period.这些仪器记录电气参数在被测量的某一特定期间内的连续值。练习：这是准备搬进城的一家人.提示：move to英文：10He went out for a walk,while I stayed at home.This is the family which is planning to

21、move to the city.Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesOhms Law and Watts Law.Ohms law determines the relationship between Voltage(V),Current(I),and resistance(R).The simple formula（公式）can be used to determine one unknown（未知）variable（变量）if the other two vari

22、ables are known.Related to this is Watts Law（瓦特定律）which includes calculations（计算）for power.10 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesOhms Law and Watts Law.Power is a measure of the overall（全部的）amount of work being done in a system in relation to（有关）time(ener

23、gy used per second每秒).In an electrical system power can be calculated by using the formula P=V I.From this you can see how the voltage and current in a system relate to the overall amount of power used.The unit of a Watt(W)is equivalent to（等于）joules per second（焦耳每秒）,therefore one Watt is equal to（等于

24、）one joule per second.10 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and Phrases10contactor kntkt n.接触器overload,uvlud vt.超载resistance rizistns n.电阻coil kil n.线圈ohmmeter um,mi:t n.电 欧姆表ohm um n.欧姆law l:n.法律；规律relationship rileinip n.关系electromotive i,lektrumutiv adj.电动势的force

25、 f:s n.力，力量actual ktul adj.真实的，实际的measure me vt.测量value vlju:n.值purely pjuli adv.纯粹地，仅仅resistive rizistiv adj.电阻式的inductive indktiv adj.感应的inductor indkt n.电感due dju:adj.由于，因为flux flks n 通量magnetic mnetik adj.有磁性的alternating:lt,neiti adj.交替的，交互的quantity kwntti n.量measurement memnt n.测量power pau n.功率

26、introduction,intrdkn n.引进；介绍condition kndin n.条件；情况alter:lt vt.改变thus s conj.因此affect fekt vt.影响consume knsju:m vt.消耗ammeter mit n.电流表voltmeter vult,mi:t n.电压表watt-meter wt,mi:t n.功率表classify klsifai vt.分类dial dail n.刻度盘pointer pint n.指针magnitude mnitju:d n.量级unknown nnun adj.未知的integrate intireit v

27、t.使成整体，求的积分 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and Phrases10Ohms law欧姆定律electromotive force电动势due to由于magnetic field磁场alternating current交流电Lesson 11 Using the MultimeterGoal Learn useful expressions for using multimeterLook and Study DialogueReadingFurther StudyWor

28、ds and Phrases Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study114Words and PhrasesA.Look up the words and phrases below in a dictionary.Fill in the blanks with both Chinese and English answers according to the pictures.test lead;AC compressor；capacitor;resistor;DC;diode1._2._3._capacit

29、or电容器AC compressor交流压缩机resistor电阻器 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study114Words and PhrasesA.Look up the words and phrases below in a dictionary.Fill in the blanks with both Chinese and English answers according to the pictures.test lead;AC compressor；capacitor;resistor;DC;d

30、iode4._5._6._4 diode二极管;5.DC直流电;6.test lead测试引线diode二极管DC直流电test lead测试引线 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study4Words and PhrasesB.Look up multimeter names below in a dictionary.Fill in the blanks with both Chinese and English answers according to the pictures.analog multimet

31、erdigital multimeter111._ 2._digital multimeter数字万用表analog multimeter模拟万用表 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesJane（B）给他的朋友Peter（A）打电话，谈起她刚刚完成的空调修理工作。A:Hello,Peters speaking.B:Peter，Im Jane.A:Hi,Jane!Whats new?B:I have just finished my first air-conditione

32、r repairing task.A:Really?Whats it like?B:An air-conditioner of our customer was not working.I checked the capacitor of compressor motor with a multimeter and founded it need replacement.11 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesJane（B）给他的朋友Peter（A）打电话，谈起她刚刚完

33、成的空调修理工作。A:How do you know that?B:A typical capacitor failure will cause a motor not to have the extra kick to get to start up.I discharged the capacitor first and tested it with a multimeter.The result showed the capacitor didnt hold a charge.A:Well done,Jane.11 Unit 3 Lesson 4 Look and Study Dialo

34、gue Reading Further Study74Words and PhrasesA.Listen to the dialogue and circle Yes or No.1.Peter has just finished air-conditioner repairing work.Yes No2.John checked the capacitor of compressor motor with an ohmmeter.Yes No3.The capacitor is failure because it didnt hold a charge.Yes No10NoNoYes U

35、nit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesB.Reorder the letters with your partner.11LettersWordsk k c i ure fail cal typi dis charge ment replace replacementkickfailuretypicaldischarge Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and Phras

36、es万用表的使用万用表的使用A multimeter is one of the most useful diagnostic tools around.Its useful in testing power supplies,but it also can be used to test fuses,resistors,and batteries.Multimeters are designed to perform many different types of electrical tests,includinga)DC voltageb)AC voltagec)Resistance(O

37、hms)d)Diodese)Amperage11 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and Phrases万用表的使用万用表的使用All multimeters are equipped with red and black test leads.When used for voltage tests,the red is attached to the power source to be measured,and the black is attached to ground.Multi

38、meters use two different readout styles:digital and analog.Digital multimeters are usually auto ranging,which means they automatically adjust to the correct range for the test selected and the voltage present.Analog multimeters must be set manually to the correct range and can be damaged more easily

39、 by overvoltage.Multimeters are designed to perform tests in two ways:in series and in parallel.Most tests are performed in parallel mode,in which the multimeter is not part of the circuit but runs parallel to it.11 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesA.Li

40、st Basic types of electrical tests with multimeter.111._2._3._4._5._AmperageDC voltageAC voltageResistance(Ohms)Diodes Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesB.Match the English with the Chinese.Draw lines.11Be equipped with central heating执行电气测试batteries in

41、series装有集中供暖resistances in parallel串联电池perform electrical tests并联电阻 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesC.Learn the important grammar and phrase in the text.1.adjust to调整到Digital multimeters are usually auto ranging,which means they automatically adjust to

42、 the correct range for the test selected and the voltage present.数字万用表通常有自动的量程，它们可以根据所选择的测试和当前电压自动调整到正确的量程。练习：所有的数值自动调整到了正确的设置。提示：values,settings英文：2.which引导非限定定语从句Most tests are performed in parallel mode,in which the multimeter is not part of the circuit but runs parallel to it.大多数的测试以并联的方式完成。在这种方

43、式下，万用表不属于（工作）电路的一部分，而是与（工作）电路并行运行。练习：上周末我去了教堂，我妹妹在那举行过婚礼。提示：get married英文：11All the values automatically adjust to the correct settings.Last weekend I went to the church,in which my sister got married.Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesDigital Multimeter

44、Operation Manual-Dos and Dontsl Use the right input jack（插孔）,function（功能）and range.l Do not take measurements that exceed（超过）the protection limit values indicated in the specifications（说明书）.l Do not touch(接触)the metal tips（尖端）of the test leads when the meter is connected to the circuit to be measure

45、d.l Do not take voltage measurement if the value between the terminals（终端）and earth ground exceeds 1000V.l Select the highest range if the value scale（等级）to be measured in the manual range is unknown.11 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and PhrasesDigital Multimete

46、r Operation Manual-Dos and Dontsl Do not connect the meter to any voltage source while the rotary selector（旋转式选择器）is in the current,resistance,capacitance（电容）,diode,continuity range.l Disconnect the test leads from the circuit under test before turning the rotary selector to change functions.l Do no

47、t measure the resistance,capacitance,diode or continuity of live circuits(通电电路).l Do not take capacitance measurements until the capacitor to be measured has been fully discharged.l Stop using the meter if any abnormalities（异常情况）or faults are observed（观测）.11 Unit 3 Lesson 4 Look and Study Dialogue R

48、eading Further Study74Words and Phrases11air-conditioner n.空调capacitor kpsit n.电容器compressor kmpres n.压缩机multimeter mltimit n.万用表replacement ripleismnt n.更换typical tipikl adj.典型的failure feilj n.故障extra ekstr adj.额外的kick kik n.反冲力discharge dist:d vt放电charge t:d n.电荷diagnostic,dainstik adj.诊断的resistor

49、 rizist n.电阻器perform pf:m vt.执行；完成diode daiud n.二极管equip ikwip vt.装备，配备lead li:d n.引线source s:s n.来源readout ri:daut n.读出digital diditl adj.数字的analog nl adj.模拟的auto:tu adj.自动的range reind vt.(在范围内)变动;n.范围automatically,:tmtikli adv.自动地adjust dst vt.调整select silekt vt.挑选present preznt vt.出现；显示，呈现manuall

50、y mnjuli adv.手动地damage dmid vt.损坏overvoltage,uvvultid n 过电压series siri:z,-riz n.串联parallel prlel n.平行 Unit 3 Lesson 4 Look and Study Dialogue Reading Further Study74Words and Phrases11start up发动DC abbr.直流电（direct current）AC abbr.交流电（Alternating Current）equip with配备test lead测试引线adjust to调整到in series串