1、正版可修改PPT課件(中職）電子專業(yè)英語第14章教學課件Warming-upI.Can you point out the name of the following pictures?II.Do you know what the following abbreviations or symbols stand for?DMMMINMAXUnit 14 DMM下一頁返回III.Talk about DMM in English. And the following patterns you can use: Do you know what a digital multimeter is?W

2、hat are the advantages of the DMM?What are the disadvantages of the DMM?What are the DMM used widely today?Text Comprehension DMM The digital multimeter (DMM) is one of the test equipment most used by technicians today. Its accuracy, expanded measurement capabilities, ease of reading, and light load

3、ing of the circuit under test make it a prime choice in most cases.Unit 14 DMM上一頁下一頁返回Some DMMs provide polarityindicated readouts and autoranging features. If the polarity being measured is negative, the readout indicates this. When used in the autoranging mode, a DMM will automatically select the

4、range with the best resolution, without the technician having to manually select the correct range. Many DMMs also offer measurement capabilities beyond simply measuring voltage, current or resistance. Some allow measurement of AC frequency, capacitor values, semiconductor transistor condition, and

5、so on.Some popular DMMs also are capable of remembering important measurement data that you want to read at a later time. For instance, there may be a “MIN, MAX” mode on the meter. This means that the meter will remember the lowest and highest readings over a period of time. Also, some meters can st

6、ore a reading in memory, then compare it to subsequent readings, and can display the difference between the memorized reading and the subsequent reading. For safety sake, some meters have a “hold the reading” feature. Unit 14 DMM上一頁下一頁返回This allows you to keep your eyes on the test probes when worki

7、ng in dangerous places for making measurements. You can then read the display when you remove the test probes and are better able to fix your eyes on the meter readout.Some of the advantages and disadvantages of the DMM are as follows:ADVANTAGESDigital readout usually prevents a reading errorCan hav

8、e “autoranging” that prevents a meter from destroying by having it on the wrong range.Can have “autopolarity” that prevents problems from connecting meter to test circuit with wrong polarityCan have excellent accuracy (plus or minus)Portable and uses internal batteriesUnit 14 DMM上一頁下一頁返回DISADVANTAGE

9、SCan be more costly to buy and operateFrequency limitationsVocabularymultimeter n. 萬用表technician n. 技術員，技師measurement n. 測量法，度量polarity n. 極性indicate vt. 指出，顯示readout n. 讀出器，讀出，讀數autoranging n. 自動量程mode n. 模式，狀態(tài)manually adv. 手工地，手制地，手控的Unit 14 DMM上一頁下一頁返回subsequent adj. 后來的，隨后的sake n. 緣故piobe n. 探測工

10、具，探測器portable adj. 便攜式的，手提式的，輕便的batteiy n. 電池，電池組，電瓶Phrases and expressionstest equipment測試設備digital multimeter （DMM）數字萬用表for instance例如for safety sake為了安全起見polarity indicate極性指標Unit 14 DMM上一頁下一頁返回Notes “most used by technicians today” 作 “test equipment” 的定語。I Choose the right answer from A, B, and

11、C according to the text. 【 】1.There is a “MIN, MAX” mode on the DMM. You use it when you want to _.A. take the averageB. know the MAXC. read the data at a later time【 】2. _is one of the test equipment most used by technicians today.A. DMMB. PMC. AM【 】3. We use _ to select the range without the help

12、of technician.A. autoranging featuresB. polarity-indicated readoutC. Not mentioned.Unit 14 DMM上一頁下一頁返回【 】4. _ usually prevents a reading error.A. Digital readout B. WOM. C. Not mentioned.【 】5. Many DMMS also offer measurement capabilities beyond simply measuring except_ .A VoltageB. current C. elect

13、ronsII True or false.1. Technicians dont like to use DMMS.2. DMMS are accurate and easy to read.3. DMMS can automatically select the range with the best resolution.4.DMMS can “remember” important data for you to read at a later time. 5.DMMS only have a MIN mode.Unit 14 DMM上一頁下一頁返回III Translate the following sentences.1. The digital multimeter (DMM) is one of the test equipment most used by technicians today.2. Some DMMs provide polarityindicated readouts and autoranging features.3. Some popular DMMs also are capable of remembering important measurement data that you want to read a