专业英语课件.ppt

Lesson 6Diodes and Diode CircuitsChunying LiZhongjiang Vocational&Technology School Teaching aims:1.To train the Ss reading ability2.To improve the Ss expressing ability.3.To talk about the lesson4.To know some basic principles of diodesPeriod 1Text explaining and practicingImportant points:Important points:Learn to talk about the principle of diodes in EnglishLearn to talk about the principle of diodes in EnglishSpecialized termsSpecialized termsvocabulariesvocabulariesDifficult points:Difficult points:HowHow to improve the Ss expressing ability to improve the Ss expressing abilityTeaching methods:Teaching methods:Explaining and teachingExplaining and teachingPractisingPractisingTeaching aids:Teaching aids:Multi-media Multi-media computercomputerModel Model Teaching procedures:Step 1 Greetings Say hello to students.then ask the student on duty to make a free talk,by this way he/she can practice his/her oral English.Step 2 Revision Check the homework.Revise the words we learned last time in lesson 6.Ask the students to read one by one.Pay attention to the pronunciation.Through this part we can consolidate what they studied yesterday.Then show them some models of diode,ask them some questions:What are they?What kinds of specific properties do they have?V-I curveHalf-wave rectifier/full-wave bridge rectifier Step 3 Text Explaining Continue to learn this Continue to learn this lesson.Explainlesson.Explain the text the text sentence by sentence by sentence.Paysentence.Pay attention to the important attention to the important specialized terms and words.specialized terms and words.1.changeinto/turninto 1.changeinto/turninto把把变成变成/转换成转换成 e.ge.g:A rectifier changes AC to DC.A rectifier changes AC to DC.2.think ofas/regardas/be treatedas 2.think ofas/regardas/be treatedas把把看看作作/当作当作 e.ge.g:Sometimes we may think of diode as a one-Sometimes we may think of diode as a one-way conductor.way conductor.3.to have(3.to have(no)trouble(in)doingno)trouble(in)doing做做(没有没有)有困难有困难/问题问题/麻烦麻烦 e.ge.g:I think I have no trouble finishing this work in I think I have no trouble finishing this work in an hour.an hour.The important specialized terms:1.A rectifier changes AC to DC.2.The diode can be treated as a one-way conductor.It has the unilateral conductivity 3.There are two waveforms:half/full waveform.(ask some students to answer the questions.)the answers are:only half of the input waveform is used in a circuit.that is called half-wave rectifier.The whole input waveform is used.this is called full-wave rectifier.4.Ask them to remember the two curves of waveforms.Step 4 PractisingSummarize what we learned just now.Ask some students to note down the important specialized terms by asking questions:1.What is the main character of diode?1.What is the main character of diode?2.What is the half-wave rectifier?2.What is the half-wave rectifier?3.What is the full-wave bridge rectifier?3.What is the full-wave bridge rectifier?4.Please draw the curve graph of the diode 4.Please draw the curve graph of the diode:Step 5 HomeworkRead the sentences and wordsFinish the Ex.on page 24