中职电子专业英语第7章教学课件

1、正版可修改PPT课件(中职）电子专业英语第7章教学课件Warming-upI.Can you point out the name of the following picture?II.Do you know what the following abbreviations or symbols stand for?L EMF HIII.Talk about Current in English. And the following patterns you can use: Do you know how electricity flows?Could you tell me how ma

2、ny kinds of current / voltage there are? And what are they?Unit 7 inductor下一页返回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 InductorIts well known that an inductor is a device to resist change in

3、current flow. It usually has low DC resistance but high AC impedance, thats to say, it passes direct current in a circuit while blocking alternating current. Its electrically opposite to the capacitor. It is measured in Henries, millihenries used commonly.Unit 7 inductor上一页下一页返回The inductor has prop

4、erties of inductance and resistance in the wire from which the inductor is wound. The amount of inductance, L, relates to the physical properties of the coil, including the length, cross-sectional area, number of turns, and types of core.When a DC voltage is first applied to a circuit with an induct

5、or present, current does not instantly rise to the value that is equal to the DC resistance of the circuit divided by the applied voltage. This delay is due to the inductors opposing any current change. Under opposite conditions, current will not abruptly decrease to zero, since the inductor opposes

6、 the current change and the collapsing field induces an EMF in the coil to attempt to prevent the current from changing. Laminated iron-core inductors, such as those used in power supplies and audio circuitry are often in henries of inductance. Powdered iron-core and variable ferrite-core inductor c

7、an have inductance ranges in millihenries. Air-core inductors are typically in the microhenries range.Unit 7 inductor上一页下一页返回Inductors find numerous applications in electronic and power systems. They are used in power supplies, transformers, radios, TVs and electric motors. They are mainly used in t

8、wo kinds of applications in power and electronic systems:(1) Filtering current ripple in a DC circuit.(2) Used as an inductive component in an AC circuit.Vocabularyinductorn.感应器 abruptly adv.突然地；意外地resistancen.电阻collapsing n.毁坏（压扁，折叠）impedancen.阻抗；全电阻laminate v.制成薄板；切成薄板(片)alternatingadj.交替的；间隔的ferr

9、iten.亚铁盐；铁酸盐propertyn.属性；道具；财产filtern.过滤器coiln.线圈；线阻ripplen.脉冲Unit 7 inductor上一页下一页返回Phrases and expressions1. be well known以而闻名2. The amount of的数量3. relate to与相关联4. be applied to被应用于5. is equal to与一致，相当6. due to由于Notes1. thats to say: 属于固定搭配，意为：“即；也就是说”。2. The inductor has properties of inductance

10、and resistance in the wire from which the inductor is wound. 电感器在其所缠绕的线圈中有电感和电阻的属性。Unit 7 inductor上一页下一页返回3. When a DC voltage is first applied to a circuit with an inductor present, current does not instantly rise to the value that is equal to the DC resistance of the circuit divided by the applied

11、 voltage. 当直流电压首次应用于带有电感器的电路时，电流值不会立即升至外加电压与直流电阻的比值。I Choose the right answer from A, B, and C according to the text. 【 】1. Its well known that a(n) _ is a device to resist change in current flow.A. inductorB. resistanceC. circuit 【 】2. The inductor has properties of _. A. inductanceB. inductance an

12、d resistanceC. resistance【 】3. Under opposite conditions, current will not abruptly decrease to _. A. the highestB. the lowestC. zeroUnit 7 inductor上一页下一页返回【 】4. _ are typically in the microhenries range.A. Air-core inductorsB. Laminated iron-core inductorsC. Powdered iron-core【 】5. They are used in

13、 _. A power suppliesB transformersC both A and BII True or false.1. Inductor is measured in Henries, millihenries used commonly.2. The amount of inductance relates to the physical properties of the coil. 3. Under opposite conditions, current will abruptly decrease to zero.4. Laminated iron-core indu

14、ctors are often in henries of inductance. 5. Inductors find little applications in electronic and power systems.Unit 7 inductor上一页下一页返回III Translate the following sentences.1. Inductor usually has low DC resistance but high AC impedance. 2. The inductor has properties of inductance and resistance in the wire from which the inductor is wound. 3. Under opposite conditions, current will not abruptly decrease to zero. 4. Air-co