广东海洋大学寸金学院10电气专业英语考试复习资料.docx

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1、1. Charge is an electrical property of the atomic particles of which matter consists, measured in coulombs. 电荷是构成物质的原子电气属性，其量纲为库伦。2. The presence of equal numbers of protons and electrons leaves an atom neutrally charged.质子和电子数量相同使得原子呈电中性。3. The voltage Uab between two points a and b in an electric

2、circuit is the energy（or work） needed to move a unit charge from a to b.电路中a，b两点间电压Uab等于从a到b移动单位电荷所需能量（或所需做的功）。4. In Fig.1-6(b) the battery is absorbing 24W, as would the case when it is being charged.图1-6中，电池就像充电情况，吸收功率24W。5. It should be noted that an ideal voltage source（dependent or independent）

3、will produce any current required to ensure that ideal voltage is as stated, whereas an ideal current source will produce the necessary voltage to ensure the stated current flow. 应该注意：一个理想电压源（独立或受控）可向电路提供任意电流以保证其端电压为规定值，而电流源可向电路提供任意电压以保证其规定电流。6. Mesh analysis is not quite as general as nodal analysi

4、s because it is only applicable to circuit that is planar. 由于网孔分析法仅适用于平面电路，故网孔分析法不像节点分析法那样通用。7. This information might involve speech and music, as in radio broadcasting, a physical quantity such as the temperature of the air in a room, or numerical data, such as the record of stock market transacti

5、ons. 这种信息或许像无线广播的演讲和音乐，或许是像室内温度的物理量，或许像股市交易记录的数字数据。8. The other kind of signal is a digital signal. A digital signal is one that can take on values within two discrete ranges. Such signals are used to represent ON-OFF or YES-NO information. 另一种信号是数字信号。数字信号是在两个离散的范围内能够呈现一定数字的信号。这两种信号常以表示开-关或是-不是信息。9.

6、 For the binary representation of the amplitude to change by one bit, an analog amplitude must change by 6.25 percent. 二进制表示量改变一位，对应的模拟量大小就一定改变了6.25%。10. The switches feed a resistive summing network which converts each bit into its weighted current value and sums them for a total current.通过开关供给一个电阻

7、性的加法电路，加法电路把每一位转变为对应的加权负载电流值并求出总电流。11. The practical switching devices have limited capabilities of rate of voltage transition and the rate of current steering. These nonabrupt transition rates give rise to power losses in the switching devices. 实际开关装置限制了电压变换速率和电流换向速率。非突变引起了开关装置的功率损失。12 The capacito

8、r is assumed to be large so that the voltage through it in steady state is nearly constant Uo. Assume that initially the switch is on, hence, the current through the switch is Is. The capacitor voltage is Uo, the voltage across the switch is zero and the diode V1 is reverse biased. 假设电容器很大，致使在稳态状况下其

9、两端的电压接近为常数Uo。假设开关开始处于闭合状态，则通过开关的电流为Is。电容器的电压为Uo，开关两端的电压为零，二极管V1反向偏置。12. All converts use effective filtering on both the input and the output to reduce the AC components from going outside the converters. 所有的滤波器均对输入和输出采用有效的滤波，以减少从变换器输出的交流成分。13. A prominent application of the Buck converter is a DC r

10、egulated power supply in which the output voltage is regulated against the variations in the load resistance and the input voltages.降压式变换器的一个著名应用是用于直流可调电源，调整其输出电压以补偿负荷电阻和输入电压的变化。14. In practical machines this rotating magnetic field is achieved by a combination of a space displacement of the winding

11、s and a time-phase displacement of the exciting voltage.在实际的电机中，旋转磁场是通过空间上交替布置是绕组和时间相位上相互交替的励磁电压来实现的。15. These coil are constructed from rectangular wire, which is bent into shape around forms and then taped. the coil is formed to the proper size so that the complete coil can be inserted into the st

12、ator slots at the time the stator is wound. 这些线圈采用矩形截面的导线构成，将它们弯曲成型后缠上绝缘带。在制作定子绕组时，线圈被做成适当的尺寸，以便将整个线圈放置入定子槽内。16. Power transformer are constructed on one of two types of cores. One type of construction consists of a simple rectangular laminated piece of steel with the transformer windings wrapped ar

13、ound two sides of the rectangle.电力变压器的铁芯分为两类。一类是由变压器绕组缠绕在一个简单的矩形钢片叠成的铁芯两边而构成。17. The second type of special transformer is a device designed to provide a secondary current much smaller than but directly proportional to its primary current.第二类特种变压器是专门用以提供比一次测电流小得多却正比于一次电流的二次电流。18. The magnetization c

14、urrent im is a current proportional(in the unsaturated region) to the voltage applied to the core, and lagging the applied voltage by 90*,so it can be modeled by a reactance Xm connected across the primary voltage source. 磁化电流im正比于作用于铁芯的电压，并滞后该电压90*，因此可以采用并联于初级电压源的电抗Xm来建模。19Most people can formulate

15、 a mental picture of a computer, but computer do so many things and come in such a variety of shapes and sizes that it might seem difficult to distill their common characteristics into an all-purpose definition. 大多数人都能描绘一台计算机，但由于计算机能做许多事情，有许多形状和规格，以致人们难以提取其共同特征形成通用的定义。20. The series of instructions

16、that tell a computer how to carry out processing tasks is referred to as a computer program, or simply a “program”.告诉计算机如何执行处理任务的一系列指令被称为计算机程序，简称为程序。21. Modern power systems are usually large-scale, geographically distributed, and with hundreds to thousands of generators operating in parallel and sy

17、nchronously.现代电力系统通常是规模大，地域分布广，具有成百上千并列同步运行的发电机组。22. The water used today may not be available in the future when its use might be more advantageous. 今天用掉的水可能在未来更有用时不能再用得到。23. In general, costs, security, and emissions are all areas of concern in power plant operation, and in practice the system is

18、operated to effect a compromise between the frequently conflicting requirements. 一般来讲，成本、安全和排放问题都是电厂运行需要考虑的方面，通常的做法是系统的运行需在各种矛盾的要求之间折中考虑。24. Constancy of speed of motor drives is particularly important for satisfactory performance of all the auxiliary drives associated with the fuel, the feed-water

19、and the combustion air supply systems. 电动机转速的恒定对燃料、给水和送风等有关的辅机设备的良好运行是特别重要的。25. The protective relay is a sensing device, which senses the fault, determines its location and then send command to the proper circuit breaker by closing its trip coil. 保护继电器是一个感知装置，它感知故障、确定故障位置，并且通过闭合相应断路器的跳闸线圈来发出跳闸命令。26

20、. The extensive use of electric clocks and the use of frequency for other timing purpose require accurate maintenance of synchronous time which is proportional to integral of frequency. As a consequence, it is necessary to regulate not only the frequency itself but also its integral.电钟和其他使用频率定时的设备的广

21、泛应用要求维持准确的同步时间，该时间正比于频率的积分。所以，不仅需要调整频率自身而且需要调整它的积分。26In an interconnected power system, the primary objectives of AGC are to regulate frequency to the specified nominal value and to maintain the interchange power between control areas at the scheduled values by adjusting the output of the selected g

22、enerators. 在互联电力系统中，AGC的主要目标是通过调节指定发电机的输出将系统频率调整到额定值，并且将区域间的功率交换维持在所要求的水平。27. Synchronous condensers and SVCs provide active compensation, the reactive power absorbed/supplied by them is automatically adjusted so as to maintain voltages of the buses to which they are connected. 同步调相机和SVCs提供有源补偿，它们吸收

23、或发出的无功功率可以自动调整以维持它们所连母线的电压水平。28. However, if due to any reason, say a fault, there is an abnormality, it is necessary that there should be a device which senses these abnormal conditions and if so, the element or component where such an abnormality has taken place is removed, i.e. deleted from the r

24、est of the system as soon as possible. 然而，由于任何原因，比如说故障，出现非正常运行状态，有必要采用一个装置来感知这种非正常状态，然后这种出现非正常状态的元件可以被切除，也就是说，尽可能快地将该元件与系统其他部分相隔离。电流 current电压 voltage电荷 charge电路 circuit电动势 electromotive force积分 integrate电位差 potential difference参考方向 reference direction瞬时功率 instantaneous power 有源的 active有源元件 active e

25、lement电阻；电阻器 risistor电容器 capacitor 电感器 inductor理想独立源 ideal independent source发电机 gennerator晶体管；半导体管 transistor放大器 amplifier阻力；阻尼 resistance伏安特性 voltage-current characterristic短路 short circuit开路 open circuit 节点分析 nodal analysis网孔分析 mesh analysis联立（方程）的 simultaneous交流 AC=alternating current直流 DC=direc

26、t current数字的 digital恒温器 thermostat模数转换 A/D=Analog-to-Digital数模转换 D/A=Digital-to-Analog传感器 transducer分压器 voltage divital半导体 semiconductor电力电子 power electronic损耗 loss变压器，变换器 transformer介质，绝缘材料 dielectric整流器 rectifier滤波，过滤 filter匝数比 turn ratio感应电机 induction machaine磁场 magnetic field 励磁电压 exciting volta

27、ge 一次绕组，原绕组 primary winding 二次绕组，副绕组 secondary winding三次绕组 tertiary winding漏磁通 leakage flux自感应 self-inductance微型计算机 mirocomputer台式计算机 desktop computer笔记本电脑 notebook computer调制解调器 modem外围设备 peripheral device操作系统 operating system并联地 in parallel变电所，变电站 substation水力发电 hydro-generation电力机组，热力单位 thermal u

28、nit无功功率 reactive power有功功率 active power 电力系统保护 power system protection继电器 relay断路器 circuit breaker热继电器 thermal relay1. What relation is between power and energy? W=Pdt2. What element is an ideal independent source?An ideal independent source is an active element that provides a specified voltage or

29、current that is completely independent of other circuit variables.3. Does the resistance value of a linear resistor vary with the current through it? Yes ,it does.4. What role does a transducer play in a signal-processing system?A transducer converts a physical or mechanical variable to an equivalen

30、t voltage or current signal as an input signal of the processing system.5. What does the output form of a system depend on?The output form of a system depends on the use to be made of the information contained in the input signals.6. Which losses are power losses in the power electronic converters c

31、omprised of?The power losses in the power electronic converters are comprised of the switching losses and the parasitic losses.7. What are the major losses items to be considered in the construction of such a equivalent circuit model？The major losses items to be considered in the construction of suc

32、h a equivalent circuit model are copper losses, eddy current losses, hysteresis losses and leakage flux.8. Which kinds can computers be categorized as?Computers can be categorized as personal computers, handheld computers, workstations , mainframes, supercomputers and servers.9. How many meanings do

33、es the term “server” have?Two meanings. It can refer to computer hardware to a specific type of software, or to a combination of hardware and software.10. What components is a modern power system comprised of?A modern power system is usually comprised of transmission lines, transformers and switchin

34、g devices, etc. 选择1.It is conventional to take the current flow as the movement of_ B.positive charges2.Electric current is the time rate of charge,measured in_. D.amperes3.The energy required to move a unit charge through an element is_. C.voltage4.The plus(+)and minus(-)signs in an electric diagra

35、m are used to define_. A.voltage polarity5.According to the passive sign convention,if the power has a plus sign,power is_by the element. B.absorbed1.An independent voltage source is a_, which maintains a specified voltage between its 2.terminals. B.two-terminal element3.Resistors are _elements. A.p

36、assive4.An ideal dependent source is an_element in which the source quantity is controlled by anther voltage or current. B.active5.There are _ possible types of dependent sources. C.fourFor a voltage source,its terminal voltage is known but its_must be determent by the external cirruit connecting wi

37、th it. B.current1.The circuit element used to model the current-resisting behavior of a material is_ C.the resisfor2.Ohms Law state that the voltage across a resistor is_the current flowing through the resistor. B.directly proportional to3.A resistor whose resistances vary with its current is known

38、as_ C.a nonlinear resistor4._ is a circuit element tith resistance approaching infinity. A.An open circuit5.An element heater draws 10 A from a 120V line.The resistance of the heater is_ C.121.Nodal analysis based on a systematic application of_,and satisfies automatically_.B.KCL,KVL2._method is cho

39、osing node voltages as circuit variables. A.Nodal analysis3.For a circuit containing N nodes and M branches,there will be_independent node voltages. B. N-14.The potential at reference node or datum node is _ in nodal analysis. A.zero5.Mesh analysis applies_to find unknown currents which are_currents

40、 B.KVL,mesh1.The voltage produced by a thermocouple pair is _ signal. B.an analog2.ON-OFF information can be represented by_signal. A.a digital3.A device that can conver an analog signal to the corresponding digital from is called_for short. A. A/D4.The thermocouple pair converts temperature differe

41、nce to a_. B.voltage5.A D/A is a device that can convert a digital signal to the equivalent_. D.analog form1.The process of quantizing the continuous values into a binary scale is called_. C.analog-to-digital conversion2._is a device that produces a voltage or a current proportional to the actual te

42、mperature. A. A temperature transducer3.The precision and the speed of an ADC are essentially_. B.incompatoble4.The precision of ADC is determined by_. D.the number of binary bits5.In Fig.2-4 the amplifier performs _functions. A.two1.The switching losses are comprised of the on-state lossed,_and the

43、 losses in the transition states. C.the off-state losses2.The typical power transistors in the on-state have_. B.0.7V3.The power transistors,as electrical switches,withstand_voltage in the off-state. D.high reverse4.The rate of voltage transition and the rate of current steering can produce _in the

44、switching ddevices. C.power losses1.The DC-DC converter converts_input to_output. B.direct current,direct current2.The Buck is a _converter. C.current step-up3.The PWM control that uses _ to control the output voltage is more popular. B.pulse width4.The gain of switch-mode linear amplifier is determ

45、ined by _voltage,and the output voltage is a linear function of _. B.the input dc source,the control voltage.1.The thumb is the direction of_in Flemings rigth-hand rule. D.the relative motion of conductor2.In induction motors the speed of the roating rotor_the speed of the rotating magnetic field.C.

46、never reaches3.When the speed of the rotor is zero,the slip of induction machine is_. C.1.04.Form-wound coils are widely used for_motors. C.large AC1.A transformer is a device that can converter one ac voltage to anther ac voltage through the action of _. B.a magnetic field2.The primary winding is connercted to _. A.the power source3.The core construction consisting of a three-legged laminated core with the winding wrapped around the centre leg is called _. B.shell form4.The transformer that takes the distribution voltage and steps it down to the final vo