机电专业英语第2版14Unit 14

1、电阻电容和电感 徐存善主编 徐存善主编 徐存善主编 If a battery is connected across a conducting material，a certain amount of current will flow through the material. This current is dependent on the voltage of the battery, on the dimensions of the sample, and on the conductivity of the material itself.1 The opposition to cu

2、rrent is called electrical resistance and is represented by the letter symbol R. The unit of resistance is the ohm, a term that is often expressed by using .One ohm is defined as that amount of resistance that will limit the current in a conductor is one ampere when the voltage applied to the conduc

3、tor is one volt. Larger amounts of resistance are commonly expressed in kiloohm (K) and in megohm (M). Resistors 电阻电阻 假若将电池连接在导电材料上，一定数量的电流将流过此材料，流过 材料的电流取决于电池的电压、材料的截面积和材料自身的电阻率。对电流的阻力 叫电阻，用字母符号R表示。电阻的单位是欧姆通常用表示。l欧姆的定义为：当 加到导体上的电压为l伏特时，将导体中的电流限制在1安培所需要的电阻值。较大 的电阻值常用千欧(K)和百万欧姆(M)表示。 徐存善主编 The resist

4、ors are made from carbon mixtures, metal films, or resistance wire and have two connecting wires attached. Variable resistors, with an adjustable sliding contact arm, are often used to control volume on radios and television sets. 电阻可以由碳混合物、金属薄膜或电阻丝制成，它有两 个连线接头。常常用带有滑动臂的可变电阻器来控制收音机 和电视机的音量。 徐存善主编 El

5、ectrical energy can be stored in an electric field. The device capable of doing this is called a capacitor or a condenser. Capacitors consist of two metal plates that are separated by all insulating material.2 If a battery is connected to both plates, an electric charge will flow for a short time an

6、d accumulate on each plate. If the battery is disconnected，the capacitor retains the charge and the voltage associated with it.3 Capacitors 电容器电容器 电能可以储存在电场中，能够储存电能的装置叫电容器。电容器是由被 绝缘材料分开的两个金属板组成。如果电池被连接在两个金属板上，电荷将 经过很短的流动而汇集在一个电极板上。假若断开电池，电容器将保持电荷 以及与电荷相关的电压。 徐存善主编 The ability of a capacitor to store

7、 electrical energy is termed capacitance. The capacitance is directly proportional to the dielectric constant of the material and to the area of the plates and inversely to the distance of the plates.4 It is measured in farads .When a changer of one volt per second across it causes the current of on

8、e ampere to flow, the condenser is said to have the capacitance of one farad. However, farad is too large a unit to be used in radio calculation, so microfarad (10-6farads) and the picofarad (10-12farads) are generally used. 电容器储存电能的能力叫电容。电容器的电容量与介质的介电常数及平板的面 积成正比，与平板间的距离成反比，其大小用法拉表示。当电容器两端的电压以每 秒1伏

9、的速率变化，产生的电流为1安培，就称电容器的电容量为1法拉。在无线电方 面的计算中，法拉的单位太大，因此常用微法(法拉)和皮法(法拉)。 徐存善主编 Inductors consist of a conducting wire wound into the form of a coil. When a current passes through the coil, a magnetic field is set up around it that tends to oppose rapid changes in current intensity.5 All coils have induc

10、tance Inductor 电感电感 电感是由绕成线圈形状的导线组成。当电流通过线圈时， 在线圈周围将产生磁场，它将阻止电流的快速变化。一切线 圈，都有电感。 徐存善主编 A coil of many turns will have more inductance than one of few turns. Also if a coil is placed on an iron core its inductance will be greater than it was without the magnetic core. The unit of induct- ance The uni

11、t of inductance is the henry. A coil has an inductance of one henry if an induced emf of one volt is induced in the coil when the current through it changes at the rate of one ampere par second.6 Values of inductance used in radio equipment vary over a wide range. 匝数多的线圈比匝数少的线圈电感更大。而且，假若线圈中放一个铁芯它 的电

12、感将比没有铁芯的线圈的电感更大。电感的单位是亨利。当流过线圈的电流 以每秒1安培的速度变化时，如果线圈中感应出1伏特感应电动势，那么，线圈的 电感就是1亨利。用于无线电设备的电感值的变化范围很大。 徐存善主编 capacitor kpsit n. 电容器 capacitance kpsitns n. 电容；电流容量 inductor indkt n. 授职者；感应器 inductance indktns n. 感应系数；自感应；电感 dimension dimenn, dai- n. 维；尺寸；vt. 标出尺寸adj. 规格的 conductivity ,kndktiviti n. 传导性；导

13、电性；传导率 opposition ,pzin n. 反对；敌对；相反；反对派 carbon ka:bn n. 碳；碳棒；复写纸 adj. 碳的；碳处理的 film film n. 胶卷；薄膜；轻烟；膜层vi. 生薄膜； volume vlju:m n. 体积；卷；册；音量；大量；adj. 大量的 徐存善主编 wire wai n. 金属丝；电线；电报 vt. 拍电报；给装电线 condenser kndens n.冷凝器；压缩器；聚合器；电容器 proportional prup:nl adj. 成比例的；相称的，n. 比例项 insulate insjuleit vt. 隔离，使孤立；物使

14、绝缘，使隔热 insulating adj. 绝缘的；隔热的（insulate的ing形式） accumulate kju:mjuleit vi. 累积；积聚 vt. 积攒 disconnect ,disknekt vt. 拆开，使分离 vi. 断开 retain ritein vt. 保持；雇；记住 dielectric ,daiilektrik adj. 非传导性的；诱电性的 n. 电介质；绝缘体 inversely inv:sli adv. 倒转地；相反地；反比例地 徐存善主编 farad frd n. 法拉（电容单位） microfarad ,maikrufrd n. 微法拉（电容量的

15、实用单位） picofarad paiku,frd n. 微微法拉（百亿分之一法拉） coil kil vt. 盘绕，把卷成圈 vi. 成圈状 n. 卷；线圈 intensity intensti n. 强烈；强度；亮度；紧张；集中程度 core k: n. 核心；果心；要点；磁心 (iron core 铁芯) induced indju:st adj. 感应的；引诱的（induce的过去分词） henry henri n.亨(利) 电感单位，略作 H pl. henrys, henries 徐存善主编 variable resistor 可变电阻器 sliding contact 滑动触点

16、dielectric constant 介电常数，电容率 magnetic field 磁场 emf abbr. n. 电动势 (Electromotive Force) 徐存善主编 1. capacitance kpsitns n. 电容；电流容量；机械容量 1) related phrases： input capacitance 输入电容 equivalent capacitance 等效电容 capacitance coupling 电容耦合 capacitance relay 电容式继电器 shant capacitance 分流电容；并联电容 anode capacitance 阳

17、极电容 how they are applied in electronic industry. 徐存善主编 2）Features: High voltage, small collector output capacitance. 特点:耐压高,集电极输出电容小。 3）Are there any precautions when adjusting the capacitance value? 调整电容值时有哪些注意事项? 4）The formula of capacitance and voltage dependence of power has been educed. 推导出了功率随

18、电容和电压变化的计算公式。 徐存善主编 2dimension n. 维；尺寸；容积 vt. 标出尺寸adj. 规格的 1) related phrases： angular dimension 角度标注 ；角度大小 linear dimension 线性尺寸 vertical dimension 垂直尺度 fit dimension 配合尺寸 under dimension 尺寸过小 dimension scale 标注比例 徐存善主编 2）Length is one dimension, and width is another. 长是一种度量，宽又是一种度量。 3) The problem

19、 of the vehicle velocity detection is resolved by one dimension video tracing. 通过一维视频跟踪的方式，解决了车辆速度检测的难题。 4) The financial dimension to market high-quality products, quality service to win customers. 维融以优质的产品占领市场，以优质的服务赢得了客户。 徐存善主编 3. volume n. 体积；卷；音量；大量；adj. 大量的 vt. 把收集成卷 1) related phrases： volume

20、 label 卷标号 bound volume 合订本 volume control 播放控制台 volume fraction 体积分率；容积比 critical volume 临界容积 stroke volume 冲程容积；心搏量 徐存善主编 2）The progress schedule compiled on the basis of volume production. 根据批量产品生产预定时间表编制的进度计划； 3）Large volume of data were gathered. 人们收集了大量的资料。 4）We buy in volume and contract earl

21、y to get the best prices. 大宗采购和尽早签订合同以获得最低货源价格。 徐存善主编 4accumulate kju:mjuleit vi. 累积；积聚 vt. 积攒 1) related phrases： accumulate experience 获取经验 accumulate points 积分 accumulate pick 多重选择 accumulate funds 积累资金 accumulate dose 总剂量，累计剂量 徐存善主编 2) When we accumulate more and more such differences between Ch

22、inese and English consciously, we will think in English when we speak English. 当我们有意识地积累了越来越多的类似的英汉差异之时，我们就开始用 英语思维来表达事物了。 3）Overall, therefore, the country did not accumulate substantial foreign currency reserves. 因此，总体来看，中国没有积累很大的外汇储备。 4）Accumulate and summarize all kinds of index completed. Do th

23、e basic and preparation job of financial budget. 积累总结各项指标完成情况的资料，做好财务预算的基础准备工作。 徐存善主编 5intensity intensti n. 强烈；强度；亮度；紧张；集中程度 1) related phrases： field intensity 磁场强度 earthquake intensity 地震强度 radiant intensity 发光度, 辐射率, 辐射强度 loading intensity 荷载强度 intensity of market position 市场地位的集中程度 徐存善主编 2) Com

24、pact, high magnetic induction intensity and long coil service life. 结构紧凑，磁感应强度高，线圈使用寿命长。 3) This reduces the labor intensity, reduce pollution, conserve water resources. 这就降低了劳动强度、减少污染、节约水资源。 4) Compact, high magnetic induction intensity and long coil service life. 结构紧凑，磁感应强度高，线圈使用寿命长。 徐存善主编 6.induc

25、ed indju:st adj. 感应的；v. 引诱；说服（induce的过去分词) 1) related phrases： induced circuit 感应电路； induced current 感生/应电流； induced radiation 感应(生)放射性； induced failure 诱发故障； induced operation 诱导运算 徐存善主编 2）Nausea and dizziness induced by motion, as in travel by aircraft, car, or ship. 晕船（车）：由运动引起的恶心和眩晕，如乘飞机、小汽车或轮船。

26、 3）The road traffic accidents induced by fatigue driving will lead to severe personal casualty and property loss. 疲劳驾驶引发的道路交通事故导致了严重的人身伤亡和财产损失。 徐存善主编 7iron core：铁芯 magnetic core：磁芯 core k: n. 果心,核心,要点 vt. 挖去(水果的)果心 1) related phrases： cable core 电缆芯线；电缆心 core diameter 芯样直径；根径 core pin 心型梢；中心销 core c

27、ompetence/competenc 核心能力 ；关键才能 徐存善主编 2）The earth have a core and a mantle around it. 地球的中心是地核，地核的周围是地幔。 3）Team spirit is the core of enterprise culture. 团队精神，是企业文化的核心。 4）The monopoly pricing power is the core meaning. 垄断最核心的意义就是定价权。 5）At the core of competitiveness, like how to attract new competiti

28、veness. 在核心竞争力不足的时候，就想怎么吸引新的竞争力。 Language points 徐存善主编 1.This current is dependent on the voltage of the battery, on the dimensions of the sample，and on the conductivity of the material itself. 流过材料的电流取决于电池的电压、材料的截面积和材料自 身的电阻率。 句中be dependent (on)：“由决定，取决于”，又如： 1) Seating load and tightness is depen

29、dent on back pressure. 阀座密封负载和紧密性与反压力相关。 Language points 徐存善主编 2) Tourism is a resource and the environment is heavily dependent on the industry. 旅游业是一个对资源和环境严重依赖的行业。 3) May you find enough inner strength to determine your own worth by yourself, and not be dependent on anothers judgments of your acc

30、omplishments. 愿你能充分发掘自身潜能，以决定你的价值所在，不要让别 人的评判埋了你的成绩。 Language points 徐存善主编 2. be defined as：“被定义为”，后接宾语，或“that”引导的宾 语从句。 如： 1）One ohm is defined as that amount of resistance that will limit the current in a conductor is one ampere when the voltage applied to the conductor is one volt. l欧姆的定义为：当加到导体上

31、的电压为l伏特时，将导体中 的电流限制在1安培所需要的电阻值。 句中第一个that作定语，第二个that引导定语从句，该从句 本身包含了一个when引导的时时间状语从句。 Language points 徐存善主编 2）A molecule may be defined as the smallest particle of matter that can exist without changing its nature. 分子可以被定义为物质在不改变其性质的情况下而能存在 的物质的最小粒子。 3) Motion may be defined as a continuous change o

32、f a body in position with respect to some other body or bodies at rest. 运动可定义为一个物体相对于另一个或几个静止物体在位 置上的连续变化。 Language points 徐存善主编 3. Capacitors consist of two metal plates that are separated by all insulating material. 电容器是由被绝缘材料分开的两个金属板组成。 句中that引导定语从句，修饰two metal plates，consist of表示“由组 成”，又如： 1）Aud

33、it risks consist of intrinsic risk, control risk and examination risk. 审计风险由固有风险、控制风险和检查风险构成。 2）Modern wind farms consist of turbines that generate electricity. 现代风力农场由发电的涡轮机组成。 Language points 徐存善主编 4. If the battery is disconnected，the capacitor retains the charge and the voltage associated with i

34、t. 如果断开电池，电容器将保持电荷以及与电荷相关的电压。 句中retain表示“保持；雇；记住”的意思。又如： 1）Help your skin retain moisture. 帮助皮肤保持水分。 2）Retain your original receipt as proof of purchase. 请保留您的原始发票作为购买证明。 3）Money has two functions, one is to retain the value of wealth, the other is an exchange value of the wealth. 金钱有两个职能，一个是保留财富价值，

35、一个是交换财富价值。 Language points 徐存善主编 5. The capacitance is directly proportional to the dielectric constant of the material and to the area of the plates and inversely to the distance of the plates. 电容器的电容量与介质的介电常数及平板的面积成正比,与平 板间的距离成反比。 a）be directly proportional to：“与成正比” b）be inversely proportional to

36、：“与成反比” 又如： 1) The resistance of a thin film/coating is directly proportional to the resistivity, and inversely proportional to the thickness. 薄膜镀膜的电阻与该镀镆的电阻系数成正比,与厚度成反比. Language points 徐存善主编 2) The magnitude of the force is found to be inversely proportional to the distance between the conductors.

37、 人们发现力的大小与施力者之间的距离成反比。 6. When a current passes through the coil，a magnetic field is set up around it that tends to oppose rapid changes in current intensity 当电流通过线圈时，在线圈周围将产生磁场，它将对抗电流 的快速变化。 句中that引导定语从句，修饰a magnetic field，it指代the coil 。oppose vt. vi. 表示“ 反对；对抗，抗争”，又如： Language points 徐存善主编 1）Small

38、 banks and some state officials strongly oppose the plan. 小银行以及某些州的官员强烈反对该方案。 2）We oppose all forms of hegemonism and power politics. 反对各种形式的霸权主义和强权政治。 Language points 徐存善主编 7. Also if a coil is placed on an iron core its inductance will be greater than it was without the magnetic core. 而且，如果线圈中放一个铁

39、芯，它的电感将比没有铁芯的 线圈的电感大。 句中than引导一个比较状语从句。inductance indktns n. “感应系数；自感应；电感”，又如： 1）DC voltage is determined by AC voltage, inductance on the AC side, and load. 直流侧直流电压是由交流电压、电感及负载决定的。 Language points 徐存善主编 2）The effects of inductance and capacitance make it necessary to carefully design all AC transmi

40、ssion systems. 电感和电容的影响，使人们必须精心地设计所有的交流输电系统。 8. A coil has an inductance of one henry if an induced emf of one volt is induced in the coil when the current through it changes at the rate of one ampere per second. 当流过线圈的电流以每秒1安培的速度变化时，如果线圈中感应出1伏特 感应电动势，那么，线圈的电感就是1亨利。 at the rate of “以的速度/速率/比率/变化率/频率

41、” 又如： Language points 徐存善主编 1）Income from property transactions shall be filed and taxed at the rate of 35%. 财产交易所得按35%扣缴率申报纳税。 2）Profits from occasional trade shall be filed and taxed at the rate of 30%. 一时贸易的盈余按30%扣缴率申报纳税。 Exercises 徐存善主编 I. Answer the following questions according to the text. 1.

42、What is called a resistor? What is the unit of resistance? 2.What is the usage of variable resistors? The resistors are made from carbon mixtures, metal films, or resistance wire and have two connecting wires attached. The opposition to current is called electrical resistance. Variable resistors, wi

43、th an adjustable sliding contact arm, are often used to control volume on radios and television sets. Exercises 徐存善主编 3. What is called a condenser? Which elements do condensers consist of? 4. How to define one farad of the capacitance? The device capable of doing this is called a capacitor or a con

44、d enser. Capacitors consist of two metal plates that are separated by all insulating material. When a changer of one volt per second across it causes the curr ent of one ampere to flow, the condenser is said to have the cap acitance of one farad. Exercises 徐存善主编 5. What are inductors made up of? How

45、 to define one henry of an inductance? Inductors consist of a conducting wire wound into th e form of a coil. A coil has an inductance of one henr y if an induced emf of one volt is induced in the coil when the current through it changes at the rate of one ampere par second. Exercises 徐存善主编 IIFill i

46、n the missing words according to the text 1. This current depends on the voltage of the battery, on the _ of the sample, and on the _ of the material itself. A _is a device designed to have capacitance. 3. Ohm is used as a unit of _. dimensionsconductivity capacitor resistance Exercises 徐存善主编 4. The

47、 larger is the emf, the more _ the capacitor stores 5. When a changer of one volt per second across it causes the current of one ampere to flow, the _ is said to have the capacitance of one _ . 6. The _ are made from carbon mixtures，metal films，or resistance wire and have two _ wires attached. capac

48、itance condenser farad resistors connecting Exercises 徐存善主编 1. 可变电阻器常用来控制收音机和电视机的音量。 2.电容器存储电能的能力叫电容。 Variable resistors are often used to control volume on radios and television sets. The ability of a capacitor to store electrical energy is termed capacitance. IIITranslate the following sentences i

49、nto English Exercises 徐存善主编 3. 任何电感都是由线圈组成，线圈的匝数越多，电感越大。 4. 电容器的电容量与介质的介电常数及平板的面积成正比, 与平板间的距离成反比。 Inductors consist of a conducting wire wound into the form of a coil. A coil of many turns will have more inductance than one of few turns. The capacitance is directly proportional to the dielectric con

50、stant of the material and to the area of the plates and inversely to the distance of the plates. 徐存善主编 And作连词，用来连接词、短语和句子，其基本意义相当于汉语 的“和”、“与”、“并且”。但在实际翻译的过程中，特别是在连 接两个句子时，它的译法很多，表达的意义可能相差甚远。如果不考 虑and 前后成分之间的逻辑关系，只用几种基本译法生硬套用，难免 造成理解上的失误，甚至把整个句子意思搞错。 l. And表示原因，例如： Laser is widely used for developing

51、 many new kinds of weapons, and it penetrates almost everything. 激光广泛用于制造各种新式武器，因为为它的穿透力很强。 徐存善主编 2. And表示因果，譬如： 1）But since a digital signal is made up of a string of simple pulses, noise stands out and easily removed. 但由于数字信号由一组简单脉冲组成，杂音明显，容易发现，因 而容易排除。 2）In l945 a new type of aeroplane engine was

52、 invented, it was much lighter and powerful than earlier engines, and enabled war planes to fly faster and higher than ever. 1945年发明了一种新型的飞机发动机。它比早期发动机要轻的多 ，功率也要大得多，因此采用这种发动机的军用飞机比以往任何时候都 飞得更快、更高。 徐存善主编 3. And表示目的，例如： It was later shown that the results of this work were by no means the ultimate，and

53、 further work has been put in hand and to provide closer control and more consistent operation in this area. 后来发现，这项研究工作的结果绝非已作定论，而进一步的研究工 作已开始，以便在这方面提供较严密的控制和较稳定的操作。 4. And表示承接，譬如： In many ways, computer is more superior than human brain, and human can rule it. 在许多方面计算机超过人脑，而人却可以控制它。 5. And表示对照，例如：

54、 例: Motion is absolute, and stagnation is relative. 运动是绝对的，而静止是相对的。 徐存善主编 6. And表示递进，譬如： 例: The electronic brain calculates a thousand times quicker, and more accurately than is possible for the human being. 电脑的运算速度比人所能达到的要快1000倍，甚至更加 准确。 7. And表示转折，例如： 例: There will always be some things that are w

55、rong, and that is nothing to be afraid of. 错误的东西在所难免，但并不可怕。 徐存善主编 8. And表示条件，譬如： Even if a programmer had endless patience, knowledge and foresight, storing every relevant detail in a computer, the machines information would be useless, and the programmer knew little how to instruct it in what human

56、 beings refer to as commonsense reasoning. 即使一个编程员很有耐心、知识和远见，把每一个有关细节都存入 计算机，如果他不懂得按人类常识推理去对计算机下达指令，机器里的 信息也还是没有用途的。 9. And表示结果，例如： Operators found that the water level was too low so they turned on two additional main coolant pumps, and too much cold water flowing into the system caused the steam t

57、o condense, further destabilizing the reactor. 操作人员发现冷却水的水位过低，就启动了另外两台主冷却泵，结 果过量的冷却水进入系统使蒸气冷凝，反应堆因而更不稳定。 徐存善主编 Analog Multimeter Digital Multimeter Bench-type Digital Multimeter Digital Storage Oscilloscope 徐存善主编 Testing and Measuring Instruments Once a particular component is suspected of being fau

58、lty, individual tests must be then performed. And the testing and measuring instruments often to be used are as follow: Multimeter A multimeter is sometimes called a volt-ohmmilliammeter. Multimeters having only volt and ohm ranges are also called volt-ohmmeters. There are two main kinds of multimet

59、ers. They are mechanical handy multimeters and digital ones. Its better for learners to use handy types, because its helpful for them to be familiar with some electronic principles. 测试仪器测试仪器 一旦怀疑某个元件出故障，就得单独做些测试。常用的测试与测量仪器如下： 万用表万用表 万用表有时候被称为伏特-欧姆-毫安表。只具有电压(伏特)和电阻档 (欧姆)的万 用表也叫伏欧表。万用表主要有两种：机械指针式万用表和数

60、字式万用表。初学者 最好使用指针式，因为指针式万用表有助于他们熟悉一些电子原理。 徐存善主编 Using a multimeter，you should first place it flat on a table and note if the meter pointer indicates exactly 0 at the extreme left end of the black scale.1 If it doesnt read 0, turn the screw on the meter movement slowly until the proper 0 reading is re