资源简介

(共53张PPT)
ELECTRICAL ENGLISH
英语
电工
Unit 1 Job and Workplace
Unit 2 Electrical Tools and Materials
Unit 3 House Wiring
Unit 4 Measuring Instruments
Contents
Unit 5 Motors and Transformers
Lesson10 Instrument Classification
Lesson 11 Using the Multimeter
Lesson 12 Using the Oscilloscope
Unit 4 Measuring Instruments
Lesson10 Instrument Classification
Goal Identify basic types and functions of
basic measuring instrument
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Further Study
Words and Phrases
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Further Study
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Words and Phrases
A. Look up the words and phrases below in a dictionary. Fill in the blanks with both Chinese and English answers according to the pictures.
contactor; electrical resistance; inductor; magnetic field; alternating current; dial
1._______________ 2._______________ 3._______________
contactor
接触器
electrical resistance
电阻
inductor
电感
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Words and Phrases
A. Look up the words and phrases below in a dictionary. Fill in the blanks with both Chinese and English answers according to the pictures.
contactor; electrical resistance; inductor; magnetic field; alternating current; dial
4._______________ 5._______________ 6._______________
dial
刻度盘
magnetic field
磁场
alternating current
交流电
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Words and Phrases
B. Look up the measuring instrument names below in a dictionary. Fill in the blanks with both Chinese and English answers according to the pictures.
ohmmeter ammeter voltmeter wattmeter
1._____________ 2._____________ 3._____________ 4._____________
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ammeter
安培表
voltmeter
伏特表
wattmeter
功率表
ohmmeter
欧姆表
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John参加电机维修的实习，正尝试确定新安装的接触器不能正常工作的故障原因，并向Peter（B）求助。
A: Peter, give me a hand.
B: What’s the trouble with you？John.
A: I wanted to make sure the new contactors weren't going to overload the 24 volt transformer, so I started checking resistance of the coils with my ohmmeter. By my reading of Ohm’s law, I got the relationship between electromotive force and resistance. But actual current measured is like wrong value So what am I doing wrong
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John参加电机维修的实习，正尝试确定新安装的接触器不能正常工作的故障原因，并向Peter（B）求助。
B: John, What a silly mistake you made! Ohm's Law in its basic form only applies to purely resistive circuits. The coil in the contactor is not a resistive circuit. It is an inductive circuit. Inductors have an additional resistance due to the flux of the magnetic field when alternating current is applied to the coil.
A: I got it.
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Words and Phrases
A. Choose the best answer
1. What was the trouble with John _________
A. The new contactors can’t work. B. He doesn’t know how to use ohmmeter.
C. The ohmmeter can’t work. D. The coils of contactors can’t work.
2. Ohm's Law in its basic form only applies to circuits.
A. purely inductive; B. purely resistive; C. any; D. Low voltage
3. Inductors have when alternating current is applied to the coil.
A. no resistance; B. an additional resistance; C. no magnetic field; D. no electromotive force
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A
B
B
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Words and Phrases
B. Reorder the letters with your partner.
Letters Words
w l a
oi c l
ic magnet
ance resist
ship relation
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relationship
law
coil
magnetic
resistance
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测量仪器的分类
The three basic quantities in the electrical measurement are current, voltage and power.
The necessary requirements for any measuring instruments are:
a) With the introduction of the instrument in the circuit, the circuit conditions should not be altered. Thus the quantity to be measured should not get affected due to the instrument used.
b) The power consumed by the instruments for their operation should be as small as possible.
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测量仪器的分类
The instrument which measures the current flowing in the circuit is called ammeter while the instrument which measures the voltage across any two points of a circuit is called voltmeter. The instruments which are used to measure the power are called power meters or watt-meters.
Electrical measuring instruments are mainly classified as:
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测量仪器的分类
a) Indicating Instruments: These instruments make use of a dial and pointer for showing or indicating magnitude of unknown quantity.
b) Recording Instruments: These instruments give a continuous record of the given electrical quantity which is being measured over a specific period.
c) Integrating instruments: These instruments measure the total quantity of electricity delivered over period of time.
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Words and Phrases
A. List the basic types of electrical measuring quantity and instrument.
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quantity instrument



power
current
voltage
integrating instruments
indicating instruments
recording instruments
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B. Read the passage again and answer the questions.
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1. The instrument which measures the voltage across any two points of a circuit is called .
2. The instruments which are used to measure the power are called .
3. The instrument which measures the current flowing in the circuit is called .
voltmeter
watt-meters
ammeter
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C. Learn the important grammar and phrase in the text.
1. While引导由含有转折关系的两个分句构成的并列句，表示对比。
The instrument which measures the current flowing in the circuit is called ammeter while the instrument which measures the voltage across any two points of a circuit is called voltmeter. 测量电路电流的仪器称为安培表，而测量电路中任意两点之间电压的仪器称为伏特表。
练习：他出去散步了，而我却待在家里。
英文：
2. which引导限定性定语从句
These instruments give a continuous record of the given electrical quantity which is being measured over a specific period. 这些仪器记录电气参数在被测量的某一特定期间内的连续值。
练习：这是准备搬进城的一家人.
提示：move to
英文：
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He went out for a walk, while I stayed at home.
This is the family which is planning to move to the city.
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Ohms Law and Watt's Law.
Ohms law determines the relationship between Voltage (V), Current (I), and resistance (R). The simple formula（公式）can be used to determine one unknown（未知）variable（变量）if the other two variables are known. Related to this is Watt's Law（瓦特定律）which includes calculations（计算）for power.
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Ohms Law and Watt's Law.
Power is a measure of the overall（全部的）amount of work being done in a system in relation to （有关）time (energy used per second每秒). In an electrical system power can be calculated by using the formula P = V I. From this you can see how the voltage and current in a system relate to the overall amount of power used. The unit of a Watt (W) is equivalent to（等于）joules per second（焦耳每秒）, therefore one Watt is equal to（等于）one joule per second.
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contactor ['k nt kt ] n.接触器 overload [, uv 'l ud] vt. 超载 resistance [ri'zist ns] n.电阻 coil [k il] n. 线圈 ohmmeter [' um,mi:t ] n. [电] 欧姆表 ohm [ um] n. 欧姆 law [l :] n. 法律；规律 relationship [ri'lei n ip] n. 关系 electromotive [i,lektr u'm utiv] adj.电动势的 force [f :s] n. 力，力量 actual [' kt u l] adj. 真实的，实际的 measure ['me ] vt. 测量 value ['v lju:] n. 值 purely ['pju li] adv. 纯粹地，仅仅 resistive [ri'zistiv] adj. 电阻式的 inductive [in'd ktiv] adj.感应的 inductor [in'd kt ] n. 电感 due [dju:] adj.由于，因为 flux [fl ks] n 通量 magnetic [m ɡ'netik] adj.有磁性的 alternating [' :lt ,neiti ] adj. 交替的，交互的
quantity ['kw nt ti] n. 量
measurement ['me m nt] n. 测量
power [pau ] n. 功率
introduction [,intr 'd k n] n. 引进；介绍
condition [k n'di n] n. 条件；情况
alter [' :lt ] vt. 改变
thus [ s] conj. 因此
affect [ 'fekt] vt. 影响
consume [k n'sju:m] vt. 消耗
ammeter [' mit ] n. 电流表
voltmeter ['v ult,mi:t ] n. 电压表
watt-meter ['w t,mi:t ] n. 功率表
classify ['kl sifai] vt. 分类
dial ['dai l] n.刻度盘
pointer ['p int ] n. 指针
magnitude ['m ɡnitju:d] n.量级
unknown [' n'n un] adj. 未知的
integrate ['intiɡreit] vt.使…成整体，求…的积分
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Ohm’s law欧姆定律
electromotive force电动势
due to由于
magnetic field磁场
alternating current交流电
Lesson 11 Using the Multimeter
Goal Learn useful expressions for using multimeter
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Words and Phrases
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Words and Phrases
A. Look up the words and phrases below in a dictionary. Fill in the blanks with both Chinese and English answers according to the pictures.
test lead; AC compressor；capacitor; resistor; DC; diode
1._______________ 2._______________ 3._______________
capacitor
电容器
AC compressor
交流压缩机
resistor
电阻器
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Words and Phrases
A. Look up the words and phrases below in a dictionary. Fill in the blanks with both Chinese and English answers according to the pictures.
test lead; AC compressor；capacitor; resistor; DC; diode
4._______________ 5._______________ 6._______________
4 diode二极管; 5. DC直流电; 6. test lead测试引线
diode
二极管
DC
直流电
test lead
测试引线
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B. Look up multimeter names below in a dictionary. Fill in the blanks with both Chinese and English answers according to the pictures.
analog multimeter digital multimeter
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1._______________ 2._______________
digital multimeter
数字万用表
analog multimeter
模拟万用表
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Jane（B）给他的朋友Peter（A）打电话，谈起她刚刚完成的空调修理工作。
A: Hello, Peter’s speaking.
B: Peter，I’m Jane.
A: Hi, Jane! What's new
B: I have just finished my first air-conditioner repairing task.
A: Really What's it like
B: An air-conditioner of our customer was not working. I checked the capacitor of compressor motor with a multimeter and founded it need replacement.
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Jane（B）给他的朋友Peter（A）打电话，谈起她刚刚完成的空调修理工作。
A: How do you know that
B: A typical capacitor failure will cause a motor not to have the extra kick to get to start up. I discharged the capacitor first and tested it with a multimeter. The result showed the capacitor didn’t hold a charge.
A: Well done, Jane.
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A. Listen to the dialogue and circle Yes or No.
1. Peter has just finished air-conditioner repairing work.
Yes No
2. John checked the capacitor of compressor motor with an ohmmeter.
Yes No
3. The capacitor is failure because it didn’t hold a charge.
Yes No
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No
No
Yes
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B. Reorder the letters with your partner.
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Letters Words
k k c i
ure fail
cal typi
dis charge
ment replace
replacement
kick
failure
typical
discharge
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万用表的使用
A multimeter is one of the most useful diagnostic tools around. It’s useful in testing power supplies, but it also can be used to test fuses, resistors, and batteries. Multimeters are designed to perform many different types of electrical tests, including
a)DC voltage
b)AC voltage
c)Resistance (Ohms)
d)Diodes
e)Amperage
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万用表的使用
All multimeters are equipped with red and black test leads. When used for voltage tests, the red is attached to the power source to be measured, and the black is attached to ground.
Multimeters use two different readout styles: digital and analog. Digital multimeters are usually auto ranging, which means they automatically adjust to the correct range for the test selected and the voltage present. Analog multimeters must be set manually to the correct range and can be damaged more easily by overvoltage.
Multimeters are designed to perform tests in two ways: in series and in parallel. Most tests are performed in parallel mode, in which the multimeter is not part of the circuit but runs parallel to it.
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A. List Basic types of electrical tests with multimeter.
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________________________________________________
________________________________________________
________________________________________________
________________________________________________
________________________________________________
Amperage
DC voltage
AC voltage
Resistance (Ohms)
Diodes
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B. Match the English with the Chinese. Draw lines.
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Be equipped with central heating 执行电气测试
batteries in series 装有集中供暖
resistances in parallel 串联电池
perform electrical tests 并联电阻
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C. Learn the important grammar and phrase in the text.
1. adjust to调整到
Digital multimeters are usually auto ranging, which means they automatically adjust to the correct range for the test selected and the voltage present. 数字万用表通常有自动的量程，它们可以根据所选择的测试和当前电压自动调整到正确的量程。
练习：所有的数值自动调整到了正确的设置。
提示：values, settings
英文：
2. which引导非限定定语从句
Most tests are performed in parallel mode, in which the multimeter is not part of the circuit but runs parallel to it. 大多数的测试以并联的方式完成。在这种方式下，万用表不属于（工作）电路的一部分，而是与（工作）电路并行运行。
练习：上周末我去了教堂，我妹妹在那举行过婚礼。
提示：get married
英文：
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All the values automatically adjust to the correct settings.
Last weekend I went to the church, in which my sister got married.
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Digital Multimeter Operation Manual- Dos and Don’ts
Use the right input jack（插孔）, function（功能）and range.
Do not take measurements that exceed（超过）the protection limit values indicated in the specifications（说明书）.
Do not touch(接触)the metal tips（尖端）of the test leads when the meter is connected to the circuit to be measured.
Do not take voltage measurement if the value between the terminals（终端）and earth ground exceeds 1000V.
Select the highest range if the value scale（等级）to be measured in the manual range is unknown.
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Digital Multimeter Operation Manual- Dos and Don’ts
Do not connect the meter to any voltage source while the rotary selector（旋转式选择器）is in the current, resistance, capacitance（电容）, diode, continuity range.
Disconnect the test leads from the circuit under test before turning the rotary selector to change functions.
Do not measure the resistance, capacitance, diode or continuity of live circuits(通电电路).
Do not take capacitance measurements until the capacitor to be measured has been fully discharged.
Stop using the meter if any abnormalities（异常情况）or faults are observed（观测）.
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air-conditioner n. 空调 capacitor [k 'p sit ] n.电容器 compressor [k m'pres ] n. 压缩机 multimeter [m l'timit ] n. 万用表 replacement [ri'pleism nt] n. 更换 typical ['tipik l] adj. 典型的 failure ['feilj ] n.故障 extra ['ekstr ] adj. 额外的 kick [kik] n.反冲力 discharge [dis't ɑ:d ] vt放电 charge [t ɑ:d ] n. 电荷 diagnostic [,dai ɡ'n stik] adj. 诊断的 resistor [ri'zist ] n. 电阻器 perform [p 'f :m] vt. 执行；完成 diode ['dai ud] n. 二极管 equip [i'kwip] vt. 装备，配备 lead [[li:d n.引线 source [s :s] n. 来源
readout ['ri:daut] n. 读出
digital ['did it l] adj. 数字的
analog [' n l ɡ] adj. 模拟的
auto [' :t u] adj.自动的
range [reind ] vt. (在…范围内)变动;n. 范围
automatically [, :t 'm tik li] adv. 自动地
adjust [ 'd st] vt. 调整
select [si'lekt] vt. 挑选
present ['prez nt] vt. 出现；显示，呈现
manually ['m nju li] adv. 手动地
damage ['d mid ] vt. 损坏
overvoltage [, uv 'v ultid ] n 过电压
series ['si ri:z, -riz] n. 串联
parallel ['p r lel] n. 平行
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start up发动
DC abbr. 直流电（direct current）
AC abbr. 交流电（Alternating Current）
equip with配备
test lead测试引线
adjust to调整到
in series串联
in parallel并联
Lesson 12 Using the Oscilloscope
Goal Learn useful expressions for using oscilloscope
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Words and Phrases
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Words and Phrases
A. Look up the words and phrases below in a dictionary. Fill in the blanks with both Chinese and English answers according to the pictures.
wave; charger; rectifier; PCB; oscilloscope; signal
1._______________ 2._______________ 3._______________
charger
充电器
PCB
印刷电路板
oscilloscope
示波器
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A. Look up the words and phrases below in a dictionary. Fill in the blanks with both Chinese and English answers according to the pictures.
wave; charger; rectifier; PCB; oscilloscope; signal
4._______________ 5._______________ 6._______________
4. rectifier整流器; 5. signal信号; 6. wave波
rectifier整流器
rectifier
整流器
signal
信号
wave
波
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Jane（A）看到Peter（B）正在研究一个充电器的电路图，于是提出了几个问题。
A: Peter, here is a battery charger circuit diagram. What’s the component in square c5
B: That’s a transformer, John.
A: Oh, I see. What will you do with the diagram, a PCB
B: No. My boss only wants me to test the battery charger with an oscilloscope.
A: I’m not quite sure where to test it.
B: At points A, B and C.
A: What’s the component in square D5
B: That’s a full-wave bridge rectifier.
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A. Listen to the dialogue and circle Yes or No.
1. Peter wants to make a battery charger.
Yes No
2. John tests the battery charger with an oscilloscope.
Yes No
3. Peter and John are studying a wiring diagram.
Yes No
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No
No
No
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B. Reorder the letters with your partner.
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Letters Words
u sq are
dge bri
oscillo scope
square
bridge
oscilloscope
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使用示波器
An oscilloscope is a type of electronic test instrument that allows observation of constantly varying signal voltages, usually as a two-dimensional graph of one or more electrical potential differences using the vertical ('Y') axis and horizontal ('x') axis, plotted as a function of time. Although an oscilloscope displays voltage on its vertical axis, any other quantity that can be converted to a voltage can be displayed as well. In most instances, oscilloscopes show events that repeat with either no change or change slowly.
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使用示波器
Oscilloscopes are commonly used to observe the exact wave shape of an electrical signal. In addition to the amplitude of the signal, an oscilloscope can show distortion, the time between two events (such as pulse width, period) and relative timing of two related signals.
Oscilloscopes are used in the sciences, medicine, engineering, and telecommunications industry. General purpose instruments are used for maintenance of electronic equipment and laboratory work.
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A. Read the passage again and answer the questions.
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1. An oscilloscope is a type of that allows observation of constantly varying signal voltages.
2. Oscilloscopes are commonly used to observe of an electrical signal.
electronic test instrument
the exact wave shape
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B. Reorder the letters with your partner.
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Letters Words
e w v a
se p ul
ri pe od
ve ob ser
func tion
try indus
industry
wave
pulse
period
observe
function
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C. Learn the important grammar and phrase in the text.
1. plot绘制，制图
An oscilloscope is a type of electronic test instrument that allows observation of constantly varying signal voltages, usually as a two-dimensional graph of one or more electrical potential differences using the vertical ('Y') axis and horizontal ('x') axis, plotted as a function of time. 示波器是一种电子测试仪器，它可以用来观察不断变化的信号电压；通常是根据时间，使用垂直（Y）轴或水平（X）轴绘制的表示一个或更多电位变化二维图形。
练习：首先，在图表上绘出温度曲线。
提示：curve
中文：
2. convert to转换为
Although an oscilloscope displays voltage on its vertical axis, any other quantity that can be converted to a voltage can be displayed as well. 尽管示波器在它的垂直轴向上显示电压，任何其它可以转换为电压的量值也可以显示。
练习：你首先必须将其换算成电信号，如电压或电流。
英文：
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Firstly，tthe temperature curve should be ploted on the graph.
You must first convert it to an electrical signal such as voltage or current.
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Troubleshooting.
A basic circuit is shown in the figure below.
Generally（一般地）electrical problems can be classified under two broad（大概的）types.
1. A connection（连接）does not exist（存在）where it should. This is an open-circuit（开路） fault（故障）and can be detected（检测）using a continuity tester
2. A connection exists where none（没有东西）should. This is called a short-circuit（短路） fault. Such fault happens due to insulation failures（失灵）and can be detected using insulation testing instruments.
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Troubleshooting.
The process（过程）of detecting these faults and correcting（改正）the circuit to restore（恢复） normal operating condition is called troubleshooting.
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charger ['t ɑ:d ] n. 充电器 square [skwε ] n. 方格 oscilloscope [ 'sil usk up] n. 示波器 full-wave全波的 bridge [brid ] n. 桥接器 rectifier ['rektifai ] n. 整流器 observation [, bz :'vei n] n. 观察 constantly ['k nst ntli] adv. 不断地，时常地 vary ['vε ri] vi. 变化 dimensional [di'men n l] adj.空间的，尺寸的 two-dimensional adj. 二维的 graph [ɡrɑ:f] n 图形 potential [p u'ten l] n. 电位 vertical ['v :tik l] adj. 垂直的 axis [' ksis] n. 轴 horizontal ['h ri'z nt l] adj. 水平的 plot [pl t] vt. 绘制
function ['f k n] n. 功能
convert [k n'v :t] vi. 转变，变换
event [i'vent] n. 结果；事件
repeat [ri'pi:t] vt. 重复
commonly ['k m nli] adv. 一般地
observe [ b'z :v] vt. 观察
exact [iɡ'z kt] adj. 准确的
wave [weiv] n. 波
amplitude [' mplitju:d] n. 振幅
distortion [dis't : n] n. 变形
pulse [p ls] n. 脉冲
width [widθ, witθ] n. 宽度
period ['pi ri d] n. 周期
relative ['rel tiv] adj. 相对的
related [ri'leitid] adj.有关系的，有关联的
industry ['ind stri] n. 产业；工业
Look and Study
Dialogue
Reading
Further Study
7
4
Words and Phrases
12
two dimensional二维的
PCB abbr. 印刷电路板（Printed circuit board）
full-wave bridge全波电桥
as a function of根据
convert to转换为

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