電子與通信技術(shù)專(zhuān)業(yè)英語(yǔ)Unit 2 lesson 7

1、Unit Electronic Instrument and Products 本單元重點(diǎn)介紹常用的電子儀器和電子設(shè)備及其應(yīng)用，主要包括萬(wàn)用表、數(shù)字電壓表、示波器、觸摸屏、液晶顯示器、智能手機(jī)、無(wú)線(xiàn)電接收機(jī)、電視、家庭影院、錄像機(jī)和數(shù)字音響等。通過(guò)本單元的學(xué)習(xí)，學(xué)生可以學(xué)到較為系統(tǒng)的關(guān)于電子技術(shù)應(yīng)用的英語(yǔ)表達(dá)，為能在真實(shí)電子技術(shù)應(yīng)用專(zhuān)業(yè)環(huán)境中應(yīng)用英語(yǔ)進(jìn)行工作打下基礎(chǔ)。TextNew wordNotesExercisesTranslationVocabulary Unit2PART1 Multimeters are very useful test instruments. By operati

2、ng a multi-position switch on the meter they can be quickly and easily set to be a voltmeter, an ammeter or an ohmmeter. They have several settings (called ranges) for each type of meter and the choice of AC or DC. Some multimeters have additional features such as transistor testing and ranges for m

3、easuring capacitance and frequency. There are two basic types of multimeters, digital and analog. Analog multimeters have a needle and the digital has a LED display. All digital meters contain a battery to power the display so they use virtually no power from the circuit under test. This means that

4、on their DC voltage ranges they have a very high resistance (usually called input impedance) of 1M or more, usually 10M, and they are very unlikely to affect the circuit under test. Measuring voltage and current with a multimeterLesson 7 Multimeters and Its UsageTextNew wordNotesExercisesTranslation

5、Vocabulary PART2Lesson 7 Multimeters and Its Usage 1. Select a range with a maximum greater than you expect the reading to be. 2. Connect the meter, making sure the leads are the correct way round. Digital meters can be safely connected in reverse, but an analogue meter may be damaged. 3. If the rea

6、ding goes off the scale: immediately disconnect and select a higher range.TextNew wordNotesExercisesTranslationVocabulary Fig.7-1 Measuring Voltage at a PointPART3Lesson 7 Multimeters and Its UsageTextNew wordNotesExercisesTranslationVocabulary Multimeters are easily damaged by careless use, so plea

7、se take these precautions: 1Always disconnect the multimeter before adjusting the range switch. 2Always check the setting of the range switch before you connect to a circuit. 3Never leave a multimeter set to a current range (except when actually taking a reading). The greatest risk of damage is on t

8、he current ranges because the meter has a low resistance. Measuring voltage at a point When testing circuits, you often need to find the voltages at various points, for example the voltage at pin 2 of a 555 timer chip (as shown in Fig.7-1). This can seem confusingwhere should you connect the second

9、multimeter lead? 1Connect the black (negative -) lead to 0V, normally the negative terminal of the battery or power supply. ExercisesPART4Lesson 7 Multimeters and Its UsageTextNew wordNotesTranslationVocabulary 2Connect the red (positive +) lead to the point you where you need to measure the voltage

10、. 3The black lead can be left permanently connected to 0V while you use the red lead as a probe to measure voltages at various points. Measuring resistance with a multimeter Another useful function of the DMM is the ohmmeter. An ohmmeter measures the electrical resistance of a circuit. If you have n

11、o resistance in a circuit, the ohmmeter will read 0. If you have an open in a circuit, it will read infinite.TextPART5New words and phrases:multimeter mltimit n. 萬(wàn)用表instrument instrumnt n. 工具，儀器，器械ammeter mit n. 安培表ohmmeter um,mi:t n. 歐姆表needle ni:dl n. 指針display ,displei n. 顯示，表現(xiàn)disconnect ,disknek

12、t v. 斷開(kāi)confusing knfju:zi adj. 使人困惑的，令人費(fèi)解的infinite infint adj. 無(wú)限的，無(wú)窮的reverse riv:s adj. 相反的pin pin n. 大頭針，針，拴precaution prik:n n. 預(yù)防，留心，警戒risk risk n. 風(fēng)險(xiǎn)，危險(xiǎn)New wordNotesExercisesTranslationVocabulary PART6Phrases and Expressionstake precautions 采取預(yù)防措施voltage ranges 電壓范圍input impedance 輸入阻抗New words

13、 and phrases:TextNew wordNotesExercisesTranslationVocabulary PART7Notes:1. By operating a multi-position switch on the meter they can be quickly and easily set to be a voltmeter, an ammeter or an ohmmeter.譯文：通過(guò)操控萬(wàn)用表上的切換開(kāi)關(guān)，可將萬(wàn)用表調(diào)定到電壓表、電壓表和電阻表?！癇y”是介詞，因此by后面要跟名詞、動(dòng)名詞或動(dòng)詞現(xiàn)在分詞。2. and they are very unlikel

14、y to affect the circuit under test.譯文：數(shù)字式萬(wàn)用表不大會(huì)影響測(cè)試中的電路?！癰e unlikely to”意為“不太可能、不大會(huì)”。3. Select a range with a maximum greater than you expect the reading to be.譯文：根據(jù)預(yù)期的讀數(shù)范圍選擇大一級(jí)的量程?！皉eading”意為“讀數(shù)”。TextNew wordNotesExercisesTranslationVocabulary PART84. When testing circuits, you often need to find t

15、he voltages at various points, for example the voltage at pin 2 of a 555 timer chip (as shown in Fig.7-1).譯文：當(dāng)我們進(jìn)行電路測(cè)試時(shí)，常常需要知道某一點(diǎn)的電壓，例如555定時(shí)器芯片2腳的電壓。在從句和主句有共同的主語(yǔ)時(shí)可將從句的主語(yǔ)省略，并將謂語(yǔ)動(dòng)詞改為動(dòng)詞現(xiàn)在分詞。從句“When testing circuits”的主語(yǔ)應(yīng)該是“you”與主句“you often need to find the voltages ”中的主語(yǔ)“you”相同，故可省略。Notes:TextNew wordN

16、otesExercisesTranslationVocabulary PART9Exercises:1.Write T (True) or F (False) beside the following statements about the text.a. Analog multimeters have a LED display and the digital has a needle. b. All digital meters contain a electrical motor to power the display so they use virtually no power f

17、rom the circuit under test.c. This means that on their DC voltage ranges they have a very high resistance of 10M or more, usually 100M, and they are very unlikely to affect the circuit under test. d. An analogue meter can be safely connected in reverse, but the digital meters may be damaged.e. Conne

18、ct the meter, making sure the leads are the correct way round.f. Always disconnect the multimeter before adjusting the range switch. 2. Fill in the missing words according to the text.a. By operating a multi-position switch on the meter they can be quickly and easily set to be a , an or an .b. They

19、have several settings (called ) for each type of meter and the choice of or .TextNew wordNotesExercisesTranslationVocabulary Exercises:c. Some multimeters have additional features such as and ranges for measuring capacitance and .d. There are two basic types of multimeters, and .e. Select a range wi

20、th a than you expect the reading to be. f. Multimeters are easily damaged by careless use, so please take the .3. Translate the following paragraph into Chinese. Measuring Resistance with a multimeter:Another useful function of the DMM is the ohmmeter. An ohmmeter measures the electrical resistance

21、of a circuit. If you have no resistance in a circuit, the ohmmeter will read 0. If you have an open in a circuit, it will read infinite.TextNew wordNotesExercisesTranslationVocabulary PART10Translation第7課 萬(wàn)用表及其使用 萬(wàn)用表是非常有用的測(cè)量?jī)x器，通過(guò)操作萬(wàn)用表的多用開(kāi)關(guān)，可以快捷而方便地將其設(shè)置為電壓表、安培表或歐姆表。每種類(lèi)型的儀表都有幾種擋位選擇（稱(chēng)為量程），還可選擇交流和直流。有些萬(wàn)用表還有一些其它功能，如測(cè)量晶體管、測(cè)量電容和頻率范圍等。