中職電子專業(yè)英語第2章教學(xué)課件

1、正版可修改PPT課件(中職）電子專業(yè)英語第2章教學(xué)課件Warming-upI. Can you point out the difference of the following pictures are?II.Do you know what the following abbreviations or symbols stand for?DC ACAIII.Talk about Current in English. And the following patterns you can use: Do you know how electricity flows?Could you tel

2、l me how many kinds of current / voltage there are? And what are they?Unit 2 Current下一頁返回Could you tell me the unit of current / voltage?What is the symbol of current / voltage?The unit / symbol of current / voltage is Text Comprehension CurrentAn electric current is the flow of electrons, which are

3、 minute negative charges of electricity, through a metal conductor. The electrons flow along a wire much the same way as water runs through a pipe. Though the electrons move from minus to plus, the electric current is conventionally considered to flow from the positive to the negative terminal in a

4、completed circuit.Its known to all that there are two types of current: DC and AC. The current which moves continuously in one direction is called a direct current. Its always associated with batteries. The electrical system in an automobile and an airplane, the telephone and the trolleybus use the

5、direct current. However, a direct current has one disadvantage. As yet, there is no easy and economical way to increase or decrease its voltage.Unit 2 Current上一頁下一頁返回At present, practically most cities make use of another type of electric current for lighting, heating, industry and other purpose. Th

6、e current flowing first in one direction and then in another. We call it an alternating current. The alternating current doesnt have this disadvantage. Using a special device, called transformer, it is possible to transform a high voltage into a low voltage or a low voltage into a high voltage. The

7、alternating current can also be changed easily into the direct current using a rectifier.Unit 2 Current上一頁下一頁返回Vocabulary1. electronn.電子2. negative n.負的，陰性的3. chargen. 負荷，電荷4. electricity n電，電學(xué)5. pipe n.管子，管道6. minusn.負號，減號，負數(shù) adj.負的7. plusn.正號，加號，正數(shù) adj.正的8. conventionallyadv. 習(xí)慣地，按照慣例9. associatev

8、t.與相關(guān)10.automobilen.汽車11. airplanen飛機Unit 2 Current上一頁下一頁返回12. trolley-busn.無軌電車13. industrialadj.工業(yè)的14.disadvantagen.缺點15. economicaladj.經(jīng)濟的16.transformern.變壓器，轉(zhuǎn)化器17.transformvt.轉(zhuǎn)換，轉(zhuǎn)變18.rectifiern. 整流器Phrases and expressions1. negative (positive) charge負(正)電荷2. positive (negative) terminal正(負)極3. D

9、C/ AC直流/交流4. make use of使用5. transforminto把轉(zhuǎn)變成Unit 2 Current上一頁下一頁返回6. minute此處不是名詞“分鐘為”; 而是形容詞，意為“微笑的”。7. much the same way as 與差不多一樣地8. 這個 “all”意為“大家；所有人”。9. be associated with意為“與.相關(guān)的（相聯(lián)系的）”。10. “Using a special device”為現(xiàn)在分詞短語作條件狀語，譯成“如果使用一種專門的設(shè)備”。I Choose the right answer from A, B, and C accord

10、ing to the text. 【 】1.A current is the flow of _.A. chargesB. positive chargesC. electrons【 】2. The current flows in a _.A. closed circuitB. open circuitC. any circuit【 】3. We use _ in the telephone.A. ACB. DCC. Not mentioned.Unit 2 Current上一頁下一頁返回【 】4. _ flows first in one direction and then in ano

11、ther.A. ACB. DC.C. Not mentioned.【 】5. _ can change the alternating current into direct current.A TransformerB ReceiverC RectifierII True or false.1. The electrons moves from plus to minus.2. The current flows from the positive to the negative terminal.3. The direct current can easily increase and d

12、ecrease its voltage.4. The transformer can transform a low voltage into a high voltage and vice versa. 5. The rectifier is used to change a direct current into an alternating current.Unit 2 Current上一頁下一頁返回III Translate the following sentences.1. The electrons flow along a wire much the same way as w

13、ater runs through a pipe.2. The electric current is conventionally considered to flow from the positive to the negative terminal in a completed circuit.3. The current which moves continuously in one direction is called a direct current.4. At present, practically most cities make use of another type of electric current for lighting, heating, industry and other purpose.5. Using a special device, called tra