《专业外语单片机方向.ppt》由会员分享,可在线阅读,更多相关《专业外语单片机方向.ppt(102页珍藏版)》请在三一文库上搜索。
1、专业英语概述,主讲教师:赵伟,掌握专业外语技能是大学基础英语学习的主要目的之一,是一种素质上的提高,直接关系到学生的求职和毕业后的工作能力。 专业外语重要性体现在多个方面,大到日益广泛的国际间的科学技术交流,小到对产品说明书的翻译。在INTERNET查找资料。 专业外语具有与基础英语不同的特点和含义。,If a mouse is installed in a computer,then the available memory space for user will reduce. 错误译法:如果让老鼠在计算机里筑窝,那么使用者的记忆空间就会减少。 专业译法:如果计算机安装了鼠标,则用户可利用
2、的内存空间就会减少。,Connect the black pigtail with the dog-house. 错误译法:把黑色的猪尾巴系在狗窝上。 专业译法:将黑色的引出线接在高频高压电源屏蔽罩上。,Control Center .Smoking Free. 错误译法:控制中心,吸烟自由。 Free 随便的,自由的 专业译法:控制中心,严禁吸烟。 Free 免除的,专业英语的基本特点,语言简练,结构严谨,表达明确,不重虚文润饰。 逻辑推理性强,原理概念清楚,段落章节分明。 专业英语的语法特色。 专业英语的特点。,非人称的语气和客观的态度,尤其是常使用It结构; 大量使用一般现在时时态和被动
3、语态; 大量使用非限定性动词,即不定式、分词和动名词; 较多使用祈使语气,即所谓的公式化表达方式; 大量使用介词短语; 条件句较多,尤其是If语句; 长句较多; 省略句较多; 表达方式一般比较简洁,很少使用很复杂的从句。,大量使用专业词汇和半专业词汇 ; Robot 机器人 resistor 电阻器 inductor 电感器 Multi-user 多用户 steady-state 稳态 大量使用词性转换; 较多使用词缀和词根,甚至用词缀和词根创造新词;,大量使用单词所写或专用符号 IT informatian technology 信息技术 CAD Computer Aided Design
4、计算机辅助设计 DVD digital video discs 数字化视频光盘 VCD Video Compact Disc 视频压缩盘片 新的专业词汇 Hypermedia 超媒体 hypertext 超文本 hyperlink 超链接,专业英语中的常用符号和数学式,4/5 four fifths 0.025 zero point zero two five 2% two percent the second power of five; five to the power two + plus;positive - minus;negative x multiplied by; times
5、, divided by = is equal to;eauals sin x sine of x ab a puls or minus b a/b a is parallel to b x2 x square;x squared ; the square of x ; the second power of x,专业英语的翻译标准,翻译首先要做到忠实、准确,要“信”。也就是说译文应避免漏译或错译,忠实正确的转达原文内容,既不歪曲,也不任意增减。同时,在表达上保持原作的风格和文体。,The importance of computer in the use of automatic contr
6、ol can not be overestimated. 初译:计算机在自动控制应用上的重要性不能被估计过高。 更正:对计算机在自动控制应用上的重要性怎么估计也不会过高。,其次,要做到通顺、流畅,要“达”。这是指译文应通顺易懂,符合汉语的规范,要和原作同样的流利自如。同时,在翻译中要避免“死译”和“硬译”,以便于他人理解。,This possibility was supported to a limited extend in the tests. 初译:这一可能性在试验中在有限程度上被支持了。 更正:这一可能性在实验中于一定程度上得到了证实。,The difference between
7、single-board microcomputer and single-chip microcomputer do not stop there. 初译:单板机和单片机的差别不停留在那里。 更正:单板机和单片机的差别不仅如此。,Amplification means the transformation of little currents into big ones,without distortion of the shape of current fluction. 初译:放大意味着由小电流到大电流的转变,而电流起伏的形状没有歪曲。 更正:所谓放大,就是把小电流变为大电流,而又不使电
8、流波形失真。,This technique provides a solution with the longest range and the maximum data rate for user. 初译:这一技术提供给用户具有目前最为广阔的传输范围和最大的数据传输速度的最为有效地解决方案。 更正:这一技术为用户提供了具有最大的数据传输距离和速度的方案。,再次,译文在忠实和通顺的基础上还应注意文采,要“雅”。要讲修辞,使译文在逻辑上严谨而流畅,语言上优美而易懂。否则就会因“言之无文,行之不远”而失去读者。 最后,无论翻译或阅读,都希望有较高的翻译速度,也就是“捷”。速度越快,对信息的获取量也
9、就越大,效率也就越高。,词汇的专业性含义强 diode 二极管,capacitor 电容, Internet 因特网; memory 内存/记忆,bus 总线/ 公共汽车,monitor 监视器/班长,order 阶次/命令/订货。,Unit1 Electrical Networks,An electrical circuit or network is composed of elements such as resistors, inductors, and capacitors connected together in some manner. If the network conta
10、ins no energy sources, such as batteries or electrical generators, it is known as a passive network. On the other hand, if one or more energy sources are present, the resultant combination is an active network. In studying the behavior of an electrical network, we are interested in determining the v
11、oltages and currents that exist within the circuit. Since a network is composed of passive circuit elements, we must first define the electrical characteristic of these elements.,Unit1 Electrical Networks,network n. 网络,电路 resistor n. 电阻器 inductor n. 电感器 capacitor n. 电容器 passive network 无源网络 active n
12、etwork 有源网络 characteristic adj. 特性(的);n. 特性曲线 Ohm n. 欧姆 Faraday n. 法拉第 electric charge 电荷 integral n. 积分 increment n. 增量 armature n. 电枢,衔铁,加固 aforementioned adj. 上述的,前面提到的,represent v. 代表,表示,阐明 amplify v. 放大 symbolic adj. 符号的,记号的 mesh n. 网孔 Kirchhoffs first law 基尔霍夫第一定律 loop current 回路电流 voltage dro
13、p 电压降 in series 串联 differential adj. 微分的;n. 微分 variable n. 变量 outline n. 轮廓;v. 提出的要点 eliminate v. 消除,对消,An electrical circuit or network is composed of elements such as resistors, inductors, and capacitors connected together in some manner. If the network contains no energy sources, such as batterie
14、s or electrical generators, it is known as a passive network. On the other hand, if one or more energy sources are present, the resultant combination is an active network. In studying the behavior of an electrical network, we are interested in determining the voltages and currents that exist within
15、the circuit. Since a network is composed of passive circuit elements, we must first define the electrical characteristic of these elements.,In the case of a resistor, the voltage-current relationship is given by Ohms law, which states that the voltage across the resistor is equal to the current thro
16、ugh the resistor multiplied by the value of the resistance. Mathematically, this is expressed as u=iR where u=voltage, V; i=current, A; R=resistance,The voltage across a pure inductor is defined by Faradays law, witch states that the voltage across the inductor is proportional to the rate of change
17、with time of the current through the inductor. Thus we have where di/dt =rate of change of current, A/s; L= inductance , H.,The voltage developed across a capacitor is proportional to the electric charge q accumulating on the plates of the capacitor. Since the accumulation of charge may be expressed
18、 as the summation, or integral, of the charge increments dq, we have the equation where the capacitance C is the proportionality constant relating voltage and charge. By definition, current equals rate of change of charge with time and is expressed as i=dq/dt. Thus an increment of charge dq is equal
19、 to the current multiplied by the corresponding time increment, or dq=i dt.,Eq.(1-1A-3 ) may then be written as where C= capacitance, F. A summary of Eqs(1-1A-1), (1-1A-2) and (1-1A-4) for the three forms of passive circuit elements is given in Fig. 1-1A-1. Note that conventional current flow is use
20、d; hence the current in each element is shown in the direction of decreasing voltage.,Active electrical devices involve the conversion of energy to electrical form. For example, the electrical energy in a battery is derived from its stored chemical energy. The electrical energy of a generator is a r
21、esult of the mechanical energy of the rotating armature.,Active electrical elements occur in two basic form: voltage sources and current sources. In their ideal form, voltage sources generate a constant voltage independent of the current drawn from the source. The aforementioned battery and generato
22、r are regarded as voltage sources since their voltage is essentially constant with load. On the other hand, current sources produce a current whose magnitude is independent of the load connected to the source. Although current sources are not as familiar in practice, the concept does find wide use i
23、n representing an amplifying device, such as the transistor, by means of an equivalent electrical circuit. Symbolic representations of voltage and current sources are shown in fig. 1-1A-2.,A common method of analyzing an electrical network is mesh or loop analysis. The fundamental law that is applie
24、d in this method is Kirchhoff s first law, which states that the algebraic sum of the voltage around a closed loop is 0, or, in any close loop, the sum of the voltage rises must equal the sum of the voltage drops. Mesh analysis consists of assuming that current-termed loop currents-flow in each loop
25、 of network, algebraically summing the voltage drops around each loop, and setting each sum equal to 0.,Unit2 The Operational Amplifier,A 运算放大器 1.课文内容简介:主要介绍专业基础课模拟电子技术基 础中运算放大器的概念,放大倍数的计算方法,理想运 放两个输入端“虚短路”和“虚断路”的概念。 2.温习模拟电子技术基础中比例运算电路的分析方法。 3.生词与短语 amplifier n. 放大器 integrated circuit 集成电路 building
26、 blocks 积木 potential n. (电)势 cascade n., v. 串联;adj. 串联的 on the order of 属于同类的,约为 trade off 换取 cumbersome adj. 麻烦的 intrinsic adj. 内在的 circuitry n. 电路,network n. 网络,电路 resistor n. 电阻器 inductor n. 电感器 capacitor n. 电容器 passive network 无源网络 active network 有源网络 characteristic adj. 特性(的);n. 特性曲线 Ohm n. 欧姆
27、Faraday n. 法拉第 electric charge 电荷 integral n. 积分 increment n. 增量 armature n. 电枢,衔铁,加固 aforementioned adj. 上述的,前面提到的,represent v. 代表,表示,阐明 amplify v. 放大 symbolic adj. 符号的,记号的 mesh n. 网孔 Kirchhoffs first law 基尔霍夫第一定律 loop current 回路电流 voltage drop 电压降 in series 串联 differential adj. 微分的;n. 微分 variable
28、n. 变量 outline n. 轮廓;v. 提出的要点 eliminate v. 消除,对消,One problem with electronic devices corresponding to the generalized amplifiers is that the gains, AU or AI, depend upon internal properties of the two-port system . This makes design difficult since these parameters usually vary from device to device,
29、 as well as with temperature. The operational amplifier, or Op-Amp, is designed to minimize this dependence and to maximize the ease of design. An Op-Amp is an integrated circuit that has many component parts such as resistors and transistors built into the device. At this point we will make no atte
30、mpt to describe these inner workings.,A totally general analysis of the Op-Amp is beyond the scope of some texts. We will instead study one example in detail, then present the two Op-Amp laws and show how they can be used for analysis in many practical circuit applications(). These two principles al
31、low one to design many circuits without a detailed understanding of the device physics. Hence, Op-Amps are quite useful for researchers in a variety of technical fields who need to build simple amplifiers but do not want to design at the transistor level. In the texts of electrical circuits and elec
32、tronic they will also show how to build simple filter circuits using Op-Amps. The transistor amplifiers, which are the building blocks from which Op-Amp integrated circuits are constructed, will be discussed.,The symbol used for an ideal On-Amp is shown in Fig.l-2A-1. Only three connections are show
33、n: the positive and negative inputs, and the output. Not shown are other connections necessary to run the Op-Amp such as its attachments to power supplies and to ground potential. The latter connections are necessary to use the Op-Amp in a practical circus but are not necessary when considering the
34、ideal Op-Amp applications we study in this unit. The voltages at the two inputs and the output will be represented by the symbols U+,U-,and U0 . Each is measured with respect to ground potential. Operational amplifiers are differential devices. By this we mean that the output voltage with respect to
35、 ground is given by the expression. U0=A(U+ - U-),where A is the gain of the Op-Amp and U+ and U- the voltages at inputs. In other words, the output voltage is A times the difference in potential between the two inputs. Integrated circuit technology allows construction of many amplifier circuits on
36、a single composite “chip” of semiconductor material. One key to the success of an operational amplifier is the “cascading“ of a number of transistor amplifiers to create a very large total gain. That is, the number A in Eq. (1-2A-1) can be on the order of 100,000 or more. (For example, cascading of
37、five transistor amplifiers, each with a gain of 10, would yield this value for A.),A second important factor is that these circuits can be built in such a way that the current flow into each of the inputs is very small. A third important design feature is that the output resistance of the operationa
38、l amplifier (Ro) is very small. This in turn means that the output of the device acts like an ideal voltage source.,We now can analyze the particular amplifier circuit given in Fig. 1-2A-2 using these characteristics. First, we note that the voltage at the positive input, U+,is equal to the source v
39、oltage , U+=Us. Various currents are defined in part b of the figure. Applying KVL around the outer loop in Fig. 1-2A-2b and remembering that the output voltage, Uo, is measured with respect to ground, we have,Since the Op-Amp is constructed in such a way that no current flows into either the positi
40、ve or negative input, I-=0. KCL at the negative input terminal then yields I1=I2 Using Eq. (1-2A-2) and setting I1=I2=I We may use Ohms law to find the voltage at the negative input, U-,noting the assumed current direction and the fact that ground potential is zero volts:,Since we now have expressio
41、ns for U+and U-,Eq. (1-2A-1) may be used to calculate the output voltage,This is the gain factor for the circuit. If A is a very large number, large enough that AR1(R1+R2), the denominator of this fraction is dominated by the AR1 term. The factor A,which is in both the numerator and denominator, the
42、n cancels out and the gain is given by the expression,This shows that if A is very large, then the gain of the circuit is independent of the exact value of A and can be controlled by the choice of R1 and R2. This is one of the key features of Op-Amp designthe action of the circuit on signals depends
43、 only upon the external elements which can be easily varied by the designer and which do not depend upon the detailed character of the Op-Amp itself. Note that if A=100 000 and (R1+R2) /R1=10, the price we have paid for this advantage is that we have used a device with a voltage gain of 100 000 to p
44、roduce an amplifier with a gain of 10. In some sense, by using an Op-Amp we trade off “power“ for “control.“,A similar mathematical analysis can be made on any Op一 Amp circuit, but this is cumbersome and there are some very useful shortcuts that involve application of the two laws of Op-Amps which w
45、e now present. 1) The first law states that in normal Op-Amp circuits we may assume that the voltage difference between the input terminals is zero, that is, 2) The second law states that in normal Op-Amp circuits both of the input may be assumed to be zero:,The first law is due to the large value o
46、f the intrinsic gain A. For example, if the output of an Op-amp is 1 V and A=100 000, then This is such a small number that it can often be ignored, and we set U+=U- . The second law comes from the construction of the circuitry inside the Op-Amp which is such that almost no current flows into either
47、 of the two inputs.,译文分析,A totally general analysis of the Op-Amp is beyond the scope of some texts. We will instead study one example in detail, then present the two Op-Amp laws and show how they can be used for analysis in many practical circuit applications(). These two principles allow one to de
48、sign many circuits without a detailed understanding of the device physics. Hence, Op-Amps are quite useful for researchers in a variety of technical fields who need to build simple amplifiers but do not want to design at the transistor level. A.对于总体上普遍的分析运算放大器已超过了许多教材范围,我们将代替详细学习一个例子的旧方法。目前,关于运算放大器的
49、有关法律指出他们怎样能用于分析实际线路的申请。这两个原则允许一个人不必详细了解这些方法技巧就可以标记很多线路。运算放大器对于调查者在调查不同科学领域都是很有用的。 B.一种完整的整体的关于运算放大器的思想是基于一些实验的结论上的。我们将要详细的学习一个例子。然后把这两个关于运算放大器的规则放在一起,可以说明他们在很多实际的思想领域是可以被利用的。这两种规则让人设计出许多电子器件。在没有对物体的物理特性有详细的了解的同时,运算放大器对于探索者来说在很大的科技领域上都是非常有用的。 C.运算放大器全面普遍的分析是超越一些教材的分析的。我们将详细的研究一下这个例子,当下,这两种运算放大器的定则,告诉人们他们可以被用来分析很多实际的电路应用。这两个定则,其中一个允许去设计一些电路而不用对它的物理设备有一个详细了解。因此,运放在很多技术领域对研究者很有用。,A totally general analysis of the Op-Amp is beyond the scope of some texts. These two principles allow
链接地址:https://www.31doc.com/p-2696406.html