电气专业英语课文翻译Word格式文档下载.docx

1、电能转换器将电能转换成光、热、机械运动等等。 Events in a circuit can be defined in terms of （or voltage） and current. When electric energy is generated, transmitted and converted under conditions such that the currents and voltages involved remain constant with time, one usually speaks of direct-current （） circuits. 电路属性

2、可以根据电动势和电流来定义。当电能在产生、传输和变换时，若电路中相关的电流和电压不随时间而变化，我们便称其为直流电路 With time-invariant currents and voltages, the magnetic and electric fields of the associated electric plant are also time-invariant. This is the reason why no of self-（or mutual-）induction appear in circuits, nor are there any displacement

3、currents in the dielectric surrounding the conductors. 在电流和电压时不变的情况下，相关电气设备的电磁场也是时不变的。这就是为什么直流电路中没有自感电动势、以及围绕在导体附近的电介质没有位移电流。 shows in simplified form a hypothetical circuit with a storage battery as the source and a lamp as the load. The terminals of the source and load are interconnected by conduc

4、tors （generally but not always wires）. 图给出了一个假设电路的简单形式：一个蓄电池作为电源、以及一个灯泡作为负载。电源和负载的终端用导体互相连接，通常这种导体是导线，但少数情况下也有例外。 As is seen, the source, load and conductors form a closed conducting path. The of the source causes a continuous and unidirectional current to circulate round this closed path. 如图所示，电源、负

5、载和导体构成了一个闭合导电回路。电源的电动势产生一个连续的单方向电流在闭合回路中流通。 The simple circuit made up of a source, a load and two wires is seldom, if ever, met with in practice. Practical circuits may contain a large number of sources and loads interconnected in a variety of ways. 这种一个电源、一个负载和两根导线组成的简单电路在实践中即使有时能遇到，也是很少见的。实际的电路包括

6、很多用不同方法连接起来的电源和负载。 To simplify analysis of actual circuits, it is usual to show them symbolically in a diagram called a circuit diagram, which is in fact a fictitious or, rather, idealized model of an actual circuit of network. Such a diagram consists of interconnected symbols called circuit element

7、s or circuit parameters. 为了简化分析，通常用电路图来象征性地表示实际的电路。实际上，电路图是实际电路的一个假设模型，或相当于一个理想模型。这样的电路图包括电路元件或者电路参数等互联符号。 Two elements are necessary to represent processes in a circuit. These are a source of E and of internal （or source） resistance RS, and the load resistance （which includes the resistance of the

8、conductors） R （）. 在直流电路中，有两个元件是有必要描绘出来处理的。这就是电源的电动势E、内阻RS，以及负载电阻R。 Whatever its origin （thermal, contact, etc.）, the source E（a） is numerically equal to the potential difference between terminals 1 and 2 with the external circuit open, that is, when there is no current flowing through the source. 无论

9、图（a）中的电动势E的原动力是什么，其大小就等于1、2两端之间的开路电压，也就是电源没有电流通过的情况。 The source is directed from the terminal at a lower potential to that at a higher one. On diagram, this is shown by arrows. 电动势从较低电压端指向较高电压端，这在图表中用箭头表示。 When a load is connected to the source terminals （the circuit is then said to be loaded） and t

10、he circuit is closed, a current begins to flow round it. Now the voltage between source terminals 1 and 2 （called the terminal voltage） is not equal to its because of the voltage drop VS inside the source, that across the source resistance RS . 当一个负载加在电源两端，同时电路闭合，就有电流开始流通。这时在电源1、2两端之间的电压不等同于电源的电动势，因

11、为这时电源内阻RS两端将产生电压降VS。 shows a typical so-called external characteristic of a loaded source （hence another name is the load characteristic of a source）. As is seen, increase of current from zero to II1 causes the terminal voltage of the source to decrease linearly 图表示带负载电源的一个典型的外特性。如图所示，当电流从0增加到I1时，引起

12、电源端电压的线性减小。 In other words, the voltage drop VS across the source resistance rises in proportion to the current. This goes on until a certain limit is reached. Then as the current keeps rising, the proportionality between its value and the voltage drop across the source is upset, and the external ch

13、aracteristic ceases to be linear. 换句话说，横跨电源内阻的电压降与电流成比例的增长，这种增长趋势一直持续到一个特定的限值。然后当电流继续增加时，电流值与横过电源的电压降之间的比例关系被扰乱，使得外特性终止线性关系。 This decrease in voltage may be caused by a reduction in the source voltage, by an increase in the internal resistance, or both. The power delivered by a source is given by th

14、e equality PS=EI, where PS is the power of the source. 电源1、2两端电压的减小可能是于电源电压的减小或电源内阻的增加引起的，也可能是两种情况共同引起的。电源提供的功率等式PS=EI表示，其中PS是电源的功率。 It seems relevant at this point to dispel a common misconception about power. Thus one may hear that power is generated, delivered, consumed, transmitted, lost, etc. I

15、n point of fact, however, it is energy that can be generated, delivered, consumed, transmitted or lost. 这个公式恰当地消除了对功率的一个普遍的误解。例如有人可能听过功率被产生、释放、消耗、传输、损耗等等。然而，实际上是能量才能够被产生、释放、消耗、传输或损耗。 Power is just the rate of energy input or conversion, that is, the quantity of energy generated, delivered, transmitt

16、ed etc per unit time. So, it would be more correct to use the term energy instead of power in the above context. Yet, we would rather fall in with the tradition. 功率只是能量输入或者转换的比率，也就是说，单位时间内产生能量、释放能量、传输能量的数量。因此，在上文中用能量这个术语代替功率会更准确些。但是，我们一般采用传统的说法。 The load resistance R（b）, as a generalized circuit ele

17、ment, gives an idea about the consumption of energy, that is, the conversion of electric energy into heat, and is defined as P= the general case, the load resistance depends solely on the current through the load, which in fact is symbolized by the function R（I）. 负载电阻R作为一个普遍的电路元件，给出了能量消耗的概念，也就是电能转化成

18、热能，定义为P=I2R。一般情况下，负载电阻只流过负载的电流决定，用方程R（I）表示。 By Ohms law, the voltage across a resistance is V= circuit analysis, use is often made of the reciprocal of the resistance, termed the conductance, which is defined as g=1/R. 从欧姆定律可知，电阻两端的电压表示为V=RI。在电路分析中，经常使用电阻的倒数，称为电导，定义为g=1/R. In practical problems, one

19、 often specifies the voltage across a resistance as a function of current V（I）,or the inverse relation I（V） have come to be known as volt-ampere characteristics. 在实际问题中，通常规定横跨电阻的电压为关于电流的方程V（I）,或者是反比关系I（V），这就是众所周知的伏安特性。 shows volt-ampere curves for a metal-filament lamp V1（I）, and for a carbon-filame

20、nt lamp V2（I）. As is seen, the relation between the voltage and the current in each lamp is other than linear . The resistance of the metal-filament lamp increases （with increase of current）, and that of the carbon-filament lamp decreases with increase of current. 图给出了金属丝灯泡和碳丝灯泡的伏安曲线。如图所示，每个灯泡的电压和电流

21、关系并不是线性的，当电流升高时，金属丝灯泡的电阻增大，碳丝灯泡的内阻减小。 Electric circuits containing components with non-linear characteristic are called non-linear. If the and internal resistances of sources and associated load resistances are assumed to be independent of the current and voltage, respectively, the external characte

22、ristic V（I） of the sources and the volt-ampere characteristic V1（I） of the loads will be linear（）.包含非线性特性元件的电路称为非线性电路。如果假定电源的电动势和内阻以及相连的负载电阻分别与电流和电压无关，那么电源的外特性V（I）和负载的伏安特性V1（I）将是线性的。 Electric circuits containing only elements with linear characteristic are called practical circuits may be classed as

23、 linear. Therefore, a study into the properties and analysis of linear circuits is of both theoretical and applied interest. 只包含具有线性特性的元件的电路称为线性电路。很多应用电路都归类为线性电路，因此，对线性电路的特性和分析的学习具有理论和实际应用的双重意义。 An operational amplifier may be treated as a single electronic component with input and output terminals,

24、 rather as transistor is. The amplifier itself consists of a number of transistor stages such as those described in other lesson, fabricated and interconnected on a single substrate, and the user has access to a limited number of terminal points. Thus, of most interest from the applications point of

25、 view are the terminal characteristics. 运算放大器可以看做一个具有输入端口和输出端口的单个电子元件，就像晶体管那样。放大其本身多级晶体管组成，这样的多极晶体管在前述课程中已经介绍，他们制作和连接在一块基板上，有几个引出端可供客户使用。从使用的角度看，人们感兴趣的是端口特性。 The name operational amplifier came about from the use to which early versions of the amplifiers were put, which was to provide electronic ana

26、logs of mathematical operations such as addition, Subtraction, Multiplication, Integration etc. Present-day usage is very much wider scope but the popular name op-amp persists. 运算放大器这个名字起源于早期放大器的用途，他被用来进行一些电子模拟数学运算，例如，加减乘积分等，如今它的使用范围已大大扩展，但运算放大器这个通用名字却流传下来。The operational voltage amplifier is repres

27、ented schematically by the triangular symbol. A0 is the voltage gain from differential input to single-ended output and is always a positive number. Phase reversals are taken into account at the input terminals, which is the reason why these are labeled + and -. The voltage at each terminal, includi

28、ng the output, may be referred to common reference, usually ground, and unless otherwise stated, this common reference will be assumed. Thus, letting V（+） represent the voltage of the positive input terminal, we may define the differential input voltage as Vid=V（+）-V（-）, and the output voltage is V0

29、=A0Vid. If, however, the differential input voltage is defined as Vid=V（-）-V（+）, the output voltage is V0=-A0Vid. 电压运算放大器可用三角形符号来表示。A0表示从差动输入端到单一输出端的电压增益，并恒为正值，考虑到在输入端可能会有反向输入的情况，所以要标上+号与-号。每个端口包括输出端口的电压，都可以选一个共同的参考点，通常选大地。除非另有说明，否则所假定的参考点就是地。这样用V+代表正相输入端对参考点的电压，而V则代表负相输入点对参考点的电压，我们可以将差动电压定义为Vid=V（+

30、）+V（-）,输出电压V0=A0Vid。然而，如果差动输入电压定为Vid=V（-）-V（+）;则输出电压V0=-A0Vid。 Because no phase reversal takes place in the circuit, the positive input terminal is termed the noninverting terminal, and because a phase reversal dose take place in the circuit, the negative input terminal is termed the inverting terminal. These terminals will always be specified in the manufacturers data sheet for an amplifier. One o