中职电子专业英语第10章教学课件

1、正版可修改PPT课件(中职）电子专业英语第10章教学课件Warming-upI.Can you explain the following picture?II.Do you know the meaning of the following phrases?1. induced voltage2. electromagnetic Induction3. magnetic fieldUnit 10 Electromagnetic Induction下一页返回III.Talk about Current in English. And the following patterns you can

2、 use: Do you know when the electromagnetic induction takes place?Could you tell me how the electricity is generated?How to call the generated voltages from induced voltages?Do you know who first discovered the induced voltage?Have you ever heard of the phrase the lines of force?Text Comprehension El

3、ectromagnetic inductionThe generation of electricity is a process of changing energy from some other form into electrical energy. And the most practical process is to convert mechanical energy into electrical energy. Generators, electric motors and transformers all depend on electromagnetic inductio

4、n.Unit 10 Electromagnetic Induction上一页下一页返回In 1831, Michael Faraday in England and Joseph Henry in the United States discovered that voltage is induced across the terminals of a conductor when the conductor is moved across a stationary magnetic field or when the magnetic field is moved across the st

5、ationary conductor.The motion between the magnetic field and the conductor must be in such a manner that lines of force are cut by the conductor. If the relative motion between the field and conductor is such that the lines of force are parallel to the motion, there is no induced EMF. That is to say

6、, in order to induce voltage, mechanical displacement must take place between a magnetic field and a conductor. However, voltages are induced in still another manner whenever the flux surrounding a conductor changes in magnitude, direction or both, voltage is induced in the conductor. In this case,

7、no mechanical action of any kind occurs, the induced voltage is the result of a change in the relationship between the flux and the conductor. A magnetic field represents stored energy, and any change in the magnetic field around a conductor can produce a reaction in the conductor, which appears as

8、an induced voltage.Unit 10 Electromagnetic Induction上一页下一页返回A magnetic field is always present around a conductor carrying a current. The magnetic field produced by the current is at right angles to the current. Conversely, a changing magnetic field is always associated with an EMF, which is at righ

9、t angles to the direction of the lines of flux. The EMF associated with a changing magnetic field is an induced EMF.Induced voltages can be developed by mechanical motion between conductors and magnetic fields, or they can be produced by changes in the amplitude or direction of a magnetic field arou

10、nd a conductor. Generally speaking, we refer to voltages developed by mechanical motion as generated voltages and voltages produced by a change in flux about a conductor as induced voltages.Unit 10 Electromagnetic Induction上一页下一页返回Vocabularygeneration n.发生，产生discover n.看出，发现generate n.发生，产生acrosspre

11、p.越过，横过process n.过程，程序mannern.方法，式样generator n.发生器motionn.运动，移动electromagnetic adj.电磁的fluxn.磁力线induce v.感应，感生represent v. 代表，表示induction n.感应reaction n. 反映，反作用力stationary adj.稳定的，稳态的conversely adv.相反的Unit 10 Electromagnetic Induction上一页下一页返回Phrases and expressionsmechanical energy机械能electrical energ

12、y电能electromagnetic induction电磁感应magnetic field磁场relative motion相对运动Notes1. in such manner此处的意思是“以这样的方式”。2. If the relative motion between the field and the conductor is such that the lines of force. 本句中field 一词前省略了magnetic ,意思是磁场和导体之间的相对运动。3. right angles 的意思是直角。4. Generally speaking, we refer to vo

13、ltages developed by mechanical motion as generated voltages这里的generated voltages意思是发生电压。Unit 10 Electromagnetic Induction上一页下一页返回I Choose the right answer from A, B, and C according to the text. 【 】1. _ discovered that voltage is induced across the terminals of a conductor when the conductor is move

14、d across a stationary magnetic field.A. Michael Faraday B. Joseph Henry C. Both A and B【 】2. If the lines of force are parallel to the motion, there is _.A. induced current B. induced voltageC. no induced EMF【 】3. Whenever the flux surrounding the conductor changes in magnitude, direction Or both, _

15、 induced in the conductor.A. currentB. voltageC. both A and B【 】4. A magnetic field is always present _ a conductor carrying a current.A. onB. aroundC. underUnit 10 Electromagnetic Induction上一页下一页返回【 】5. We refer to voltages developed by mechanical motion as _.A generated voltageB induced voltageC a

16、lternating voltageII True or false.1. The generation of electricity is always a process of changing electric energy into some other forms of energy.2. The motion between the conductor and the magnet must be in such a manner that the magnet are “cut” by the conductor.3. It has been stated that no mag

17、netic field is present around a conductor carrying a current.4. Induced voltages can be developed by mechanical motion between conductors and magnetic fields.5. Voltage is induced in a conductor when the flux surrounding a conductor changes in direction.Unit 10 Electromagnetic Induction上一页下一页返回III T

18、ranslate the following sentences.1.The generation of electricity is a process of changing energy from some other form into electrical energy.2. The motion between the magnetic field and the conductor must be in such a manner that lines of force are cut by the conductor.3. In order to induce voltage, mechanical displacement must take place between a magnetic field and a conductor.4. A magnetic field represents stored energy, and any change in the magnetic field around a conductor can produce a