1.1专业英语翻译
计算机专业英语教程(第5版)翻译完整版
计算机专业英语教程（第5版）翻译完整版1.1 A Closer Look at the Processor and PrimaryStorage仔细看看处理器和主存储器We have learned that all computers have similar capabilities and perform essentially the same functions, although some might be faster than others. We have also learned that a computer system has input, output, storage, and processing components; that the processor is the “intelligence” of a computer system; and that a single computer system may have several processors. We have discussed how data are represented inside a computer system in electronic states called bits. We are now ready to expose the inner workings of the nucleus of the computer system — the processor.我们已经知道，所有的计算机都具有相似的能力，并且在本质上执行相同的功能，尽管一些可能会比另一些快一点。
我们也知道，一个计算机系统具有输入，输出，存储和处理部件；处理器是一个计算机系统智能核心，并且一个计算机系统可以有许多个处理器。
我们已经讨论过如何在计算机系统内部，用被称作“位”的电子状态来表现数据，现在我们要弄明白计算机系统的核心，即处理器，的内在的工作方式。
自动化专业英语原文和翻译
自动化专业英语原文和翻译Title: Original Text and Translation of Automation Professional EnglishIntroduction:In the field of automation, it is essential to have a good command of professional English, as many resources and documents are written in English. In this article, we will explore the original text and translation of automation professional English, providing a comprehensive guide for those looking to improve their language skills in this area.1. Original Text and Translation of Automation Terminology1.1 The original text of automation terminology includes terms such as PLC (Programmable Logic Controller), HMI (Human-Machine Interface), and SCADA (Supervisory Control and Data Acquisition).1.2 The translation of these terms into other languages must be accurate and consistent to ensure clear communication in an international context.1.3 It is important for professionals in the automation industry to be familiar with these terms in both English and their native language to facilitate effective communication with colleagues and clients.2. Original Text and Translation of Automation Standards2.1 Automation standards, such as ISO 9001 and IEC 61131, are crucial for ensuring quality and safety in automation systems.2.2 Translating these standards accurately is essential to ensure compliance with regulations and best practices in different countries.2.3 Professionals in the automation industry should be well-versed in the original text of these standards and their translations to ensure the successful implementation of automation projects worldwide.3. Original Text and Translation of Automation Documentation3.1 Automation documentation, including user manuals, technical specifications, and maintenance guides, is often written in English.3.2 Translating this documentation accurately is essential to ensure that users and technicians can understand and operate automation systems effectively.3.3 Professionals in the automation industry should be proficient in both the original text and translated versions of documentation to facilitate training, troubleshooting, and maintenance of automation systems.4. Original Text and Translation of Automation Research Papers4.1 Research papers on automation topics are often published in English-language journals and conferences.4.2 Translating these papers accurately is crucial for sharing knowledge and advancements in the field of automation with a global audience.4.3 Professionals in the automation industry should be able to read and understand original research papers in English and be familiar with translations in other languages to stay informed about the latest developments in the field.5. Original Text and Translation of Automation Software5.1 Automation software, such as CAD (Computer-Aided Design) and CAM (Computer-Aided Manufacturing) programs, often have interfaces and documentation in English.5.2 Translating this software accurately is essential for ensuring that engineers and technicians can use these tools effectively.5.3 Professionals in the automation industry should be proficient in both the original text and translated versions of automation software to maximize their productivity and efficiency in their work.Conclusion:In conclusion, having a good command of professional English in the field of automation is essential for effective communication, compliance with standards, and staying informed about the latest developments. By understanding the original text and translations of automation terminology, standards, documentation, research papers, and software, professionals in the industry can enhance their language skills and excel in their careers.。
测绘遥感专业英语翻译（1）
1.1 What is Remote Sensing?So, what exactly is remote sensing? For the purposes of this tutorial, we will use thefollowing definition:"Remote sensing is the science (and to some extent, art) of acquiring information about the Earth's surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information."1.1什么是遥感？那么，究竟什么是遥感？这篇教程的目的，我们将使用下面的定义：“遥感科学（在某种程度上，艺术）获取地球表面信息，而不必接触它。
这是通过检测和记录反映或发出能量和处理，进行分析，并应用的信息。
”In much of remote sensing, the process involves an interaction between incident radiation and the targets of interest. This is exemplified by the use of imaging systems where the following seven elements are involved. Note, however that remote sensing also involves the sensing of emitted energy and the use of non-imaging sensors.在许多遥感，过程包括入射辐射和感兴趣的目标之间的相互作用。
水处理专业英语翻译理论
专业英语翻译理论
POPs persistent organic pollutants 持久性有机污染物 TSP total suspended particle 总悬浮颗粒 TKN total Kjeldahl nitrogen 总凯氏氮 UASB up flow anaerobic sludge blanket 上流式厌氧污泥床 MBR membrane bioreactor 膜生物反应器 SBR sequencing batch reactor 间歇式活性污泥法
科学家深信一切物质都是不灭的 b. They are quite content with the data obtained from the experiment. 他们满足于试验中所获得的数据 c. We are not sure about the effect of this parameter on the quality of the effluent. 我们不能确定这个参数对出水水质的影响
专业英语翻译理论
2.1.4 语言习惯的转换 E.g.: a. Magnetism is used to measure the coldest temperature. 磁性可用来测很低的温度 b. Light-colored things reflect more light than dark-colored things. 浅色物体反射的光比深色物体多
专业英语翻译理论
3.1.2. 形容词译为动词
1. 英语中表示感觉、知觉、信念的词，如familiar、 confident、sensible of等在句中作表语时，译成动词。
a. Scientists are confident that all matter is indestructible.
电气专业英语翻译
Foundation of PLC1.1 THE CENTRAL PROCESSING UNITAlthough referred to as the brain of the system, the Central Processing Unit in a normal installation is the unsung hero, buried in a control cabinet, all but forgotten.1.1.1 Basic FunctionalityIn a programmable controller system, the central processing unit(CPU) provides both the heart and the brain required for successful and timely control execution. It rapidly and efficiently scans all of the system inputs, examines and solves the application logic, and updates all of the system outputs. In addition, it also gives itself a checkup each scan to ensure that its structure is still intact. In this chapter we will examine the central processing unit as it relates to the entire system. Included will be the various functional blocks in the CPU, typical scan techniques, I/O interface and memory users, power supplies, and system diagnostics.1.1.2 Typical Function Block InteractionsIn practice, the central processing unit can vary in its architecture, but consists of the basic building block structure illustrated in Fig.1.1.The processing section consists of one or more microprocessors and their associated circuitry. While it is true that some of the luxury of using microprocessors, most modern systems use either a single microprocessors such as the AMD 2903, usedin a bit slice architecture. This multiple microprocessor system to break the control system tasks into many small components which can beexecuted in parallel. The result of this approach is to achieve execution speeds that are orders of magnitude faster than their single-tasking counterparts. In addition to efficiently processing direct I/O control information and being programmable, the real advantage that microprocessor-based system have over their hardwired relay counterparts is the ability to acquire and manipulate numerical data easily. It is this attribute that makes programmable controllers the powerhouses that they are today in solving tough factory automation problems. The factory of tomorrow will run efficiently only if quality information about process needs and status of the process equipment are known on a realtimes basis. This can and will come about only if the unit level controllers, including programmable controllers, are empowered with the ability to collect, analyze, concentrate, and deliver data about the process. As the market continues to exhibit this demand, manufactures are likely to outfit their controllers with more and more variable memory, and enhanced instruction sets to perform these tasks.The memory segment shown in Fig.1.1 refers to the programmable controller‟s active storage medium. This can be either volatile or nonvolatile in design, and can be configured and used in a variety of ways for both executive program storage, with which the system executes its instructions, and application program storage, for the actual control program.The power supply shown here is used for providing sufficient electrical current for the various semiconductors and other power-consuming devices on one or more of the CPU circuit boards. It can be arranged in a number of different physical ways. It may be located in the same chassis in which the CPU boards are located, or can be mounted in a stand-alone fashion, connected externally to the CPU chassis. Depending on the particular manufacturer‟s configuration, it may also provide power for some of the I/O function, as wellas the CPU.1.1.3 Scan TechniquesBy definition and design, the programmable controller is dedicated to the continuous, repetitive task of examining the system inputs, solving the continuous, repetitive task of examining the system inputs, solving the current control logic ，and updating the system outputs. This task is referred to as scanning (sometimes called sweeping), and is accomplished in slightly different ways in each manufacturer‟s programmable controller. Since many of the variations are not material to the basic functionality of the system, we will only examine the basic varieties.Fig.1.2 shows the functional operation of a typical scan mechanism. You‟ll notice that the I/O servicing is at the end of the scan cycle, and is also an integral part of the scan timing. This type of scan is referred to as synchronous scan and is used with very fast machines that can update all of the I/O without lengthening the scan time materially. A typical scan time in a modern programmable controller ranges from 10~100 ms (milliseconds). Most controllers have a mechanism, watchdog timer, to measure the scan length each cycle and normally 150~250 ms. Referring to Fig.1.1 again, the synchronous scan contains four other actives in addition to the I/O scan. Housekeeping refers to a small number of routine chores performed by the programmable controller to ensure that its internal structure is still healthy and functioning properly. Next comes the communication windows to allow structured communications to other devices in the system, or externally. Included in this group would be the programming device, special microprocessor-based communications modules to allow ultimate communication of the programmable controller system to another intelligent device. Next in linecomes the executive routine, in which the actual base intelligence of the system is used to interpret the current control program. This interpretation is then used in the next step to solve the current control logic program. The last step of this basic scan process is to integrate the currently interpreted control logic program with the most current input statuses from the I/O scan, and to update the output statuses with the current results.The primary variation of this basic scanning technique comes from architectures that service and update I/O with a separate processor, asynchronous to the main logic solution scan. This alternative is common in systems where serial communication is used to control and update racks of remotely mounted I/O. It is also used where all of the I/O is serial, and run in multiple asynchronous scanning technique has the advantage that it allows extensive flexibility in configuring a programmable controller system for a particular application need. It has the disadvantage that while the basis scan rate maybe fast enough to suit an application, the I/O scan(s) actually be longer than the primary CPU scan. This can cause problems in a fast acting system in that the logic solution can occur with relatively “old”input data from the remote I/O channel. While this is at times bothersome, the more dramatic case involves a peculiarity of some programmable controllers in that they may allow input and output data to be updated on separate time bases, providing the possibility of “bad” logic solutions and unpredictable machine actions.As part of the basic CPU structure, a number of error checking procedures are used to maintain a high level of integrity in the communications between itself and its subsystems. This can involve both the internal subsystems, such as the memory, and so-called external subsystems, for example the I/O system. The more common error-checking schemes are outlined below. The first and most is parity. This is used on many communication link subsystems to detecterrors by examining the number of “ones” in each byte of information received, and comparing the total number in any one byte to a predetermined choice of even or odd parity. This corresponds to the total of ones in the byte summing to an even or odd number. This has the advantage of being able to detect a single-bit error, that is where a zero or one has changed state during some operation; but cannot detect two single but opposing bit changes in a byte of memory that cancel each other out and method for error checking, involves the examination of a block of memory for errors as compared to an individual word as done in parity checking. The procedure involves the adding of a single word of memory to a block that is unique to that block. Common varieties of the checksum are the Cyclic Redundancy Check(CRC) and the parity check is that it more efficiently uses memory. The third error checking method that we will consider is Error Detection and Correction (EDC). It is used in the more sophisticated programmable controllers provided by a few manufacturers today. In essence it involves a number of complex error correcting codes implemented in the hardware. The Error Detecting and Correcting method has the added advantage that it can sense and correct single-bit error, while only sensing double bit errors.1.1.4 I/O ControlToday‟s modern programmable controller includes a sophisticated method to control the CPU‟s execution of the Input/Output chain. This is referred to as I/O control, or sometimes Bus control. This is actually handled in different ways, depending on the type and style of controller involved. In the small programmable controller, the I/O servicing is performed as an integral part of the primary microprocessor used to control all of the major functions. In medium and large-sized systems, it is common to include a microprocessorboard or subsystem to handle the execution of the I/O updating. This is especially important in the systems that update I/O separately, or synchronously from the main scan.Regardless of the way it is achieved, the I/O control, or updating, is performed for the same reasons. For a successful scan sequence, an accurate execution of the signal level communication to the physical Input and Output modules is required. It is then, and only then, that any changes in the I/O status can be physically updated to actuators or from the sensors.1.1.5 Memory-uses and StructureFig.1.1 shows how the programmable controller memory relates to the other functional block in the CPU. It is memory, along with a microprocessor to exercise it, that separates today‟s programmable controller from its predecessor. Current advances in memory allows both the rapid creation and efficient editing of control programs used to run the manufacturing processes. Different types of memory are used in a variety of programmable controllers for different application or design reasons. Let‟s examine some of them in detail.There are two basic memory categories used by programmable controllers, or for that matter, any microprocessor-base system. They are volatile and nonvolatile. V olatile means that the contents of the memory have no means to remain intact without an external power source connected to maintain the data integrity. Nonvolatile means of the memory remain intact without an external power supply.The segments of memory in a programmable controller system are straightforward.Application Memory. Also called logic memory, it is the section ofmemory used to store the actual control program that the controller uses to control the manufacturing process. This control program is usually created by the system user.Data Table Memory. This term collectively refers to the variable (register) memory, and the input /output status or image tables. The variable memory contains timer and counter values, along with any data used in mathematical calculations performed by the application program. The I/O image tables contain, as the name suggests, a representation of the actual input/output point status, either on or off.Executive. Also called firmware (or just firmware), this section of memory contains the base intelligence of the system. The executive program supervises the basis chores of the programmable controller system including communications with subsystems, control program interpretation and execution, CPU diagnostics, and other housekeeping tasks included in every scan.Scratch Pad. This is a temporary memory area used by the system to store the step-by-step and interim results obtained through some calculations. In some systems, the scratch pad memory contains the programmable controller statistics, such as memory size, amount used, and any active diagnostic flags set. Various segments of the programmable controller use different memory types to accomplish different design or application purposes. Below .we shall examine a sample of memory types, and contrast their use in programmable controllers.Read Only Memory (ROM). This memory was one of the first commercially variable nonvolatile memory types used in microprocessor-based system. ROM get its name from the fact that the memory can be read from (information extracted), but cannot be written into (information placed in). A number of manufacturers of programmable controllers use ROM memory tostore the executive programs. This is because it normally to store the executive programs. This is because it normally requires no adjustment or editing once the system is shipped from the manufacturer. ROM is rarely, if ever, used as application memory, and cannot be used as data table or scratch pad memory because it cannot be updated with data from the operation of the programmable controller execution.Random Access Memory (RAM). This is a volatile memory, but has the advantage over ROM of being capable of being written to as well as read from. It is for this reason that it is sometimes called read/write memory. Any location within the memory can be accessible. Because it is volatile, the memory contents will be lost if power is lost. With a properly designed battery backup system, RAM can retain its current contents during large controllers are normally expandable from one memory size to their maximum size. Small controllers are normally are normally fixed in their memory size. Size of the memory capacity must be examined relative to the word size (8 bit or 16 bit) and utilization. While it is clear that twice the information can be stored in a 16 bit word than in an 8 bit byte, it may not be immediately clear that some controllers utilize memory more efficiently than others. For example, a normally open contact and its associated reference address (e.g. Input 1), may use in 8 bit each for storage. Combined, they consume one 16 bit word. Some controllers may use more memory than this for these instructions or others. In a large program, these inefficiencies can build on each other to cause a poor utilization of the system memory. A careful analysis of the various programmable controller models is required to 20%~40% of memory size to be specified to allow for modifications and later expansion. This analysis, combined with knowledge of the application needs, will allow for an intelligent choice of programmable controller.The memory of a programmable controller is organized in what is called a memory map. This segments, through a process known as partitioning, the memory into functional units. All manufactures use a slightly different technique in designing their controller‟s memory map. Some have variable partitions while others are fixed. All, however, are designed to segment the following functional areas:Executive program(s)Scratch padInput/output image tablesData tablesApplication programWe will now elaborate, in overview fashion on each of the memory map segments. As noted earlier, some controllers offer the user the flexibility (sometimes considered a constraint) of being able to vary the partitions within the memory map. This, in essence, allows the user or system builder to customize the sizes of the application, data table, and other memory segments to suit the particular application. Other controllers offer a preconfigured system, making assumptions about appropriate sizes for the various memory segments and their associated partitions. This eliminates the need for the user to deal with this sometimes confusing operation. As the architecture of programmable controllers continues to evolve, it is likely that the variable partition method will gain favorable momentum. This is likely because it accommodates a wider variety of operating systems and application programs since it can be tailored more effectively. This more flexible future may manufactures with special application software to accomplish an industry specific solution.Executive. This is the basic intelligence of the programmable controller. It allows any application program instructions to be interpreted and acted upon. Itis transparent to the user and is almost never considered to be included in the manufacturers rated memory sizes.Scratch Pad. Also transparent to the user, this memory allows interim computations and some system configuration parameters to be established.Input/output Image Tables. This is one of the most basic and straightforward segments in the memory map. This section of memory contains a stored representation of both the internal and external I/O …points.‟An internal point is an input or output that is used only in an internal control logic process, and is not directly associated with the physical I/O modules. An external point is one that is directly associated or mapped to a physical I/O module, which in turn is physically connected to a sensor or actuator. These tables of the I/O are accessible and viewed by the programming device and some other programmable controller peripherals. They can then be observed or manipulated directly for program creation, editing, or later troubleshooting after the system has been installed. This memory segment is normally partitioned to some default value corresponding to the maximum I/O capacity of the programmable controller. The view seen on the programming device screen is the most current information on the status of the I/O, as it changes the application program instructions and real world environment.Data Tables. Sometimes called the register tables, this segment of system memory contains the variable references used in the execution of the application program. Formatted in 16 bit words (8 bit in older systems), this word include storage of timer and counter accumulated values, in some cases timer and counter preset values, variable storage references for mathematical functions, storage of analog values converted to digital, storage of BCD or ASCⅡinformation, and so on. This segment, in controllers that allow it, is sized by the user to trade-off application program size.Application Program. This segment contains the actual ladder logic control program. Hence it is sometimes called the logic memory section. Again variable in size for some systems, it is created, edited, and later viewed during operation with the help of the programming device using contacts, coils, and other references, and then is converted to machine level code for use by the central processing unit. There are many techniques and devices to accomplish this task.可编程序控制器(PLC)的基础1.1 中央处理单元虽然被称为大脑的系统、中央处理单元在一个正常的安装是无名英雄，被埋在一个控制柜,几乎被忘记了。
电气自动化专业英语全文翻译
电气自动化专业英语全文翻译第一部分:电子技术第一章电子测量仪表电子技术人员使用许多不同类型的测量仪器.一些工作需要精确测量面另一些工作只需粗略估计rough estimates.有些仪器被使用be used to仅仅solely是确定线路是否完整.最常用的测量测试仪表有:电压测试仪voltage testers,电压表voltmeters,欧姆表ammeters, ohmmeters 连续性测试仪continuity testers,兆欧表megohmmeters,瓦特表wattmeters还有瓦特小时表所有测量电值的表基本上都是电流表. 他们测量或是比较通过他们的电流值. 这些仪表可以被校准calibrate并且设计了不同的量程scale,以便to读出期望的数值.1.1 安全预防safety precaution仪表的正确连接对于使用者的安全预防和仪表的正确维护是非常重要的. 仪表的结构construction和操作的基本知识能帮助使用者按安全工作程序safe working order来对他们正确连接和维护.许多仪表被设计的只能用于直流或只能用于交流,而其它的则可交替使用interchangeably.注意:每种仪表只能用来测量符合设计要求的电流类型. 如果用在不正确的电流类型中可能对仪表有危险并且可能对使用者引起伤害.许多仪表被设计成are constructed to只能测量很低的数值,还有些能测量非常大的数值.警告: 仪表不允许超过它的额定rated最大值maximum limit. 不允许被测的实际数值超过exceed仪表最大允许值的要求再强调也不过分overemphasized.超过最大值对指针indicating needle有伤害,有害于interfere正确校准proper calibration,并且在某种情况下and in some instances 能引起仪表爆炸explode造成result in对作用者的伤害.许多仪表装备了are equippedwith过载保护over correct protection.然而,通常情况下电流大于仪表设计的限定仍然是危险的hazardous.1.2 基本仪表的结构和操作许多仪表是根据电磁相互作用electromagnetic interaction的原理动作的.这种相互作用是通过流过导体的电流引起的(导体放置在永久磁铁permanent magnet的磁极poles之间) .这种类型的仪表专门适合于is suit for直流电direct current.不管什么时候电流流过导体, 磁力magnetic force总会围绕导体形成is developed. 磁力是由在永久磁铁力的作用下起反应react的电流引起.这就引起指针的移动.导体可以制成线圈coil,放置在永久磁铁磁极之间的枢钮(pivot 中心)上.线圈通过两个螺旋型spiral弹簧springs连在仪器的端子上.这些弹簧提供了与偏差成正比proportional的恢复力deflection.当没有电流通过时,弹簧使指针回复到零.表的量程被设计来指明被测量的电流值.线圈的移动(或者是指针的偏移)与线圈的电流值成正比.如果必须要测量一个大于线圈能安全负载的电流,仪表要包含旁路bypass circuit 或者分流器shunt.分流器被容纳在仪表盒内或者连接到外部.例子一个仪表被设计成最大量程scale是10A.线圈能安全负载0.001A,那分流器必须被设计成能负载9.999A.当时.001A 流过线圈时指针指示10A.图1.1(A)说明了一个永久磁铁类型仪表.图1.1(B)显示了一个外部分流器连接到仪表端子上. 永久磁铁类型仪表可以被用作安培表或者电压表. 当量程被设计成指示电流并且内阻internal resistance保持最小时, 这个表可以作为安培表用. 当量程被设计成指示电压, 内阻相对relatively高一些时, 这个表可以用来测量电压值.注意:不管如何设计,指针移动的距离取决于线圈的电流值.为了让这类表用在交流电中,在设计时必须作微小的改动.整流器rectifier可以把交流变成直流电. 整流器合并incorporate进仪表中并且量程要指示出正确的交流电压值. 整流器类型的仪表不能用于直流电中并且它一般被设计成电压表.如图1.2,电测力计electrodynamometer是另一种能用于交流电alternating current的既能作安培表也能作电压表的仪器.它由两个固定线圈stationary coils和一个移动线圈movable coil构成consist of. 这三个线圈通过两个螺旋型spiral弹簧串联in series with在一起. 这个弹簧支撑住移动线圈.当电流流行性过线圈时移动线圈顺时针方向in clockwise direction移动.电测力计因为属永久磁铁型仪表it is in permanent magnet-type meters, 量程不是均匀分布的the scale is not divided uniformly. 作用在动线圈上的力根据流过该线圈的电流平方the square of the current flowing through the coil来变化vary with.有必要在量程开始比量程结束分割的密一点.分割点之间距离越大, 仪表的读数越精确.争取strive for 精确的读值an accurate reading是重要的.移动叶片moving-vane结构是仪表的另一种类型.电流流过线圈引起cause两个铁片iron stripes(叶片)磁化to become magnetized.一个叶片是可动的,另一个是固定的sationary.在两个叶片间的磁的作用引起可动叶片扭转turn.移动的数值取决于线圈的电流值.警告:所有描述的取决于磁力作用的仪器,都不要放置在另一个磁性物质附近.它的磁力可能对引起仪表故障或者导致测量值不准确.1.3 测量仪器的使用电压表a voltmeter是设计来is designed to测量measure电路applied a current的电压electrical pressure或者通过元器件across a component的压降voltage drop. 电压表必须与被测量的电路或元器件并联in parallel with.1.3.1 压力检验计(电压检测计)交-直流电压检验计是一种相当粗糙crude但对电工electrician来说很有用的仪器.这种仪器指示电压的近似值.更常见类型指示的电压值如下:AC,110,220,440,550V,DC,125,250,600V. 许多这种仪器也指示indicate直流电的极性polarity.那就是说(i.e=that is)电路中的导体是阳性positively(正)的还是阴性negatively(负) .电压检验计通常用来检验check公共电压common voltages,识别identify接地导体grounded conductor,检查to check for被炸毁的保险丝blown fuses,区分distinguish AC 和DC. 电压检验计很小很坚固rugged,比一般的电压表average voltmeter容易携带和保存.图1.31.4 描述了depict用电压检验计检查保险丝的用法methods.为了确定电路或系统中的导体接地, 把测试仪连接在导体和已建立的地之间. 如果测试仪指示了一个电压值,导体没有接地.对每一个导体重复这个步骤continue this procedure直到until零电压zero voltage出现is indicated(见图1.5) .为了确定任意两个导体间的近似电压值,把测试仪连接在导体之间.警告:要认真读并遵守电压检验计提供supplied的说明书instructions.1.3.2 电压表电压表比电压检验计测量更精确. 因为电压表与被测量的电路或元件并联, 必须有相对高一点的电阻. 内阻要保证通过仪表的电流最小. 流过仪表的电流越小, 对电路特性electrical characteristics的影响effect越小.仪表的灵敏度sensitivity用符号O/V 表示is stated.这个数值越高仪表的质量越好.高灵敏度可使电路特性的改变减到最小.电工使用的仪表精确度在95%到98%之间.这个精确度范围对大多数应用是满意的.然而, 电力工作者力求strive to obtain最精确的可能读数是重要的. 一个精确读数可以在仪表盘上显示standing directly in front of the meter face也可以直接读出来.如果在指针后面有镜子,调整视线的角度直到指针在镜子中看不到映象.如要更精确可以使用数字表.电压表有与电压检验计同样的应用. 电压表比电压检验计更精确. 因而, 也支持更多的应用. 例如,如果一个建筑物的供电电压低于正常值slightly below normal,电压表能指示出这个问题.电压表也用来确定馈电线on feeder和支线电路导体branch circuit conductors的压降值voltage drop.电压表有时有不只一个量程. 选择一个能更精确测量的量程很重要. 选择器开关范围达到这个目的.注意:开始用一个适当的高一点的量程,然后逐渐降低到在限定范围之内的最低量程.设定选择器开关在可用的最低量程上能使读数达到最精确.使用仪表之前,要检查仪表确保指针指在零上.在仪表盘下面有一个调整螺钉an adjustment screw.一个轻微的扭动就能使指针偏移.扭转调整螺钉使指针对准零线.当在DC 中使用电压表时,保持maintain正确proper的极性是很重要的.大多数的直流电源和仪表都用颜色标记color coded极性polarity.红色指示阳极,黑色指示阴极.如果电路和元件的极性未知,触一下端子的导线leads观察observing指针indicating needle.如果指针犹豫着试图attempts to摆动,仪表导线连接就要颠倒一下be reversed.警告:不要让仪表连接反的极性polarity reversed.1.3.3 安培表安培表是用来测量电路或部分电路的电流数量的. 他与被测电路元件串联连接. 仪表的电阻必须非常低这样不会影响restrict流过电路的电流. 当测量很灵敏的设备的电流, 安培表电流的轻微改变可能会引起设备的故障.安培表象电压表一样, 也有一个调零的调整螺钉. 许多仪表也有镜子帮助assist使用者保证读数精确in obtaining an accurate reading.安培表常用来找出过载或者开路.他们也用来平衡线路的负荷loads on multiwire circuits 和确定故障位置malfunctions.安培表总是与被测电路或元件串联连接.如果使用在DC 下要检查极性.图 1.6(A)显示了安培表测量电路的电流.图 1.6(B)显示的是AC 安培表.Chap2 固体功率器件的基本原理2.1 引言(绪论) 本章将集中讨论固态功率器件或功率半导体器件,并且只研究它们在采用相控(电压控制) 或频率控制(速度控制)的三相交流鼠笼式感应电机的功率电路中的应用.2.2 固态功率器件有五种用于固体交流电机控制中的功率元器件: (1) 二极管(2) 晶闸管(例如:可控硅整流器SCR) (3) 电子晶体管(4) 门极可关断晶闸管(GTO) (5) 双向可控硅晶闸管SCR 和双向可控硅一般用于相位控制(相控) .各种二极管,晶闸管SCR,电子晶体管,门极可关断晶闸管的联合体用于频控.这些器件的共性是:利用硅晶体形成的薄片构成P-N 结的各种组合.对二极管,SCR, GTO 一般P 结叫正极N 结叫负极;相应的电子晶体管叫集电极和发射极.这些器件的区别在于导通和关断的方法及电流和电压的容量. 让我们根据他们的参数简单看一下这些元器件. 2.2.1 二极管图 2.1 显示了一个二极管,左边部分显示的是在硅晶体中的一个PN 结,右边显示的是二极管的原理图符号. 当P 相对于N 是正时,由于节上有一个相当低的压降,前向电流开始流动.当极性相反时, 只有一个极小的反向漏电流流动.这些用图 2.2 阐明.前向电压通常大约有1V,不受电流额定值的影响. 二极管正向导通电流的额定值取决于其尺寸和设计, 而这二者是根据器件散热的要求来确定的,以保证器件不超过最大结温(通常为200C) . 反向击穿电压是二极管的另一个重要参数. 它的值更取决于二极管的内部设计而不是它的物理尺寸. 注意:一个二极管只有当加上正向电压时才会正向导通.它没有任何固有(内在的)的方法控制导通的电流和电压值. 二极管主要用在交流电路中作整流器,这意味着它们把AC 整流成DC,同时产生的直流电流和电压值没有固有的控制方法.单二极管可用额定值到4800A 和最大反向电压1200V, 2000A 最大反向电压4400V. 2.2.2 晶闸管图 2.3 显示了晶闸管(一般也叫可控硅)的PN 结排列和它的原理图符号.注意这不同的结从正到负是PNPN,还有一个门极连到了内部的P 层. 如果没有连门极,并且阳极加反向电压,从正极到负极就没有电流通过.这是因为内部P 结由于未通电而工作在阻断电路.这种情况对于正向阻断状态也是正确的.然而,当阳极是正的并且正信号作用到门上,则电流将从正极一直流向负极即使门极没有正信号. 换言之, 门极能打开晶闸管但不能关断它. 关断晶闸管的唯一方法是通过外部方式在正极强加上一个零电流. 因此在前向导通只能通过强加零电流停止方面, 晶闸管与二极管是相似的.然而,晶闸管与二极管在如何启动前向导通方面是不同的. (1)阳极是正(2)门时刻是正.这个特性暗指了术语"可控硅" . 图 2.4 阐明了晶闸管的稳态伏安特性.注意反向电压和反向泄漏电流的形状与二极管的很相似.反向电压导通时比二极管的高,通常有 1.4V.阻断状态也有一个极小的前向泄漏电流. 在二极管中,稳态电流值是由器件的性能和底座(散热器)散发的热量确定的.晶闸管的最大结温比二极管要低,大约在125C.这意味着在同样的额定电流下,加上 1.4V 的前向压降,晶闸管比二极管的前向压降大的多.单晶闸管可用额定值在最大反向电压2200V 超过2000A,在在最大反向电压4000V 超过1400A. 2.2.3 电子晶体管(电子管) 图2.5 列出了一个典型功率电子管的结排列,原理符号图和伏安特性.如果集电极为正, 除非在基电极和发射极间有电流才有电流从集电极到发射极. 与晶闸管比较, 只有在基极有电流时, 电子管没有从集电极到发射极的自锁电流. 基极开路, 集电极到发射极将阻断电流. 功率电子管与晶闸管在控制前向导通的启动时相似. 它与晶闸管不同的地方在于它能控制关断和交流电机频率控制所必需的换向. 注意伏安特性没有显示反向特性.一般的,一个反向分流二极管连在发射极和集电极之间, 以保护电子管受反向电压伤害.功率电子管的可用额定值是最高反向电压1000V400A. 2.2.4 门极可关断晶闸管GTO 图 2.6 显示了GTO 的原理符号.GTO 与晶闸管的相似处在于PNPN 结的排列和前向电流的操作.如果阳极是正的,导体的启动是通过作用在门上的正脉冲.然而硅片和结是利用特殊特性设计的,所以即使阳极保持正值,加到门上的强负电流作用迫使前向电流阻断.GTO 常用的瞬间额定值是PRV1200V2400A.2.2.5 双向可控硅图2.7 显示了双向可控硅的原理符号图.一个双向可控硅由一个特殊的晶闸管包(包含前向和反向晶闸管)组成,它的操作由一个门极控制.他们常用在调光器电路中或者作为继电器的开关, 这样截止态下很小的泄漏电流不会引起其它控制器的误操作. 随着增加电流容量可控硅的可用性使他们用于交流电机的相位控制中. 2.3 功率半导体容量功率器件在稳态交流电机马力范围大于600V 时如何用,用在哪里摘要显示在表 2.1 中. 马力额定值基于没有并联的器件. 2.4 功率半导体的物理特性在物理特性条件下,有三类最常用的功率半导体: (1)栓接式(2)薄片或冰球式(3)绝缘散热器类型.他们的共同特征是需要与其它器件有物理联系.这器件叫散热器,为了保持结温在设计值内把内部热量散发出去.散热器吸收结的热量通过散热片,轮片(螺旋桨叶片) 或者液体冷却剂发散出去.液体冷却剂几乎从不用于600V 级的固态交流电动机控制中,而且也不包含在我们的讨论中. 这三类功率半导体的不同在于它们如何安装, 他们如何与散热器连接. 2.4.1 栓接式螺纹部分可能是PN 结的一部分,或者是与有源电子部分电子绝缘.在任一种情况下,螺纹部分常常插入散热器的螺纹孔. 栓接式器件在小马力额定值下常用来作为直接功率控制器件, 在大马力额定值下常用来作为辅助保护器件.在后一种情况下,它们常直接安装在较大器件使用的散热器上,如冰球式设计. 2.4.2 冰球式器件典型冰球式功率器件可能是二极管, 可控硅或GTO. 尺寸范围直径从近似25MM 到100MM. 每一个平坦的面即不是P 也不是N 结.热传递和导电从这表面产生.冰球式器件典型安装是联接铝型材的散热器.特别的箝位电路,联接绝缘混合剂和扭矩扳手都是需要的,用来确定光热传递和电导率. 由于栓接式和冰球式器件的散热器都能传递电流, 他们必须与机械底托电子绝缘. 轮片能加到散热器上增加热量排放并且增大固定负荷状态的完成. 由于散热器能在同样电压水平下作为功率器件, 冰球式和栓接式的固态AC 电动机控制必须通过附件(外壳)供给.附件(外壳)必须有合适的通风口或热交换器使得热量能散发.它不会用在放在安全封套中的用法,例如象NEMA12 的密封盒或相似的外围物. 2.4.3 绝缘散热器件绝缘散热器功率器件可能是二极管,可控硅,GTO,三极管或双向可控硅.单个的包包含器件的联合体,在内部以线加固.区别的特征是术语"绝缘散热器" .有一个铝底盘在每个包下面.这个底板与功率器件之间是导热并绝缘的.结的大部分热量传给了铝盘.这个底板依次安装在第二个更大的散热底板上.这个更大的散热底板在对面有鳍状表面. 绝缘散热器的设计使它自己是个完全封闭的设计. 他们也有经过预包装的已经内部加固过的复合器件的优点. 他们的缺点是通过底部安装的底板散热的能力有限, 所以固定负荷状态必须小于开放的散热器—安装在冰球式器件上. 尽管如此, 绝缘散热器在一般应用和器件容量的使用上迅速增长. 在较高的左上角的排列是唯一的, 同样它联合了有所有封闭设计的绝缘散热器概念的冰球式的优点(例如,易替换,易互换) .它也被恰当的称为"开放块状"模式. 2.5 换流在深入的讨论实际的固态交流电机的控制之前, 将换流的概念和种类阐述清楚是必要的. 换流的不同类型指所有讨论的固态电动机控制. 换流是功率半导体器件中负载电流被截止或停止流动或转换到另一回路的过程. 有以下三种换流方式: (1)自然或线电压换流(2)负载换流和(3)强制换流. 2.5.1 自然或线换流图 2.8 显示了功率半导体电路把AC 转换成DC.这个列举chap 3 模拟电子3.1 介绍3.1.1 模拟和数字电子的对比我们已经研究了晶体管和二极管作为开关设备怎样处理被以数字形式描述的信息(数字信息) .数字电子象用电力控制开关那样使用晶体管: 晶体管被饱和或者切断.动态区域只是从一个状态到另一个状态的过渡. 对比起来, 模拟电子取决于晶体管和其他类型放大器的动态区域. 希腊词根"analog" 意味着" 以一定的比例" ,在这里表示信息被编码成与被描述的量(被表达量) 成正比的电信号. 在图 3.1 中我们的信息是某种音乐,是乐器的激励和回响自然发起(引起) .被传播出的声音在于空气分子的有规则的运动并且被最好作为声波理解. 在话筒(扩音器)的振动膜里的这些产生的运动,依次产生一个电信号.电信号的变化与声波成比例(在电信号方面的变化是声波的成比例表现) .电信号被通过电子放大,即利用输入放大器的交流电能将信号的功率放大. 放大器的输出驱动一个录音磁头并且在磁盘上产生波浪状的槽沟. 如果整个系统是好的,空气的一切声变将被记录在磁盘上,当记录被通过一个相似的系统播放时,信号通过一个扬声器作为声音能量再传播出来,结果原始音乐被如实的再现了. 基于模拟原则的电子系统形成一类重要的电子仪器. 收音机和电视的广播是模拟系统的典型例子,许多电子仪器也是模拟系统,它们的应用包括偏差检测(应变计量器) ,运动控制(测速机)和温度测量(热电耦) .许多电子仪器---电压表,欧姆表,安培表和示波器利用了模拟技术,至少部分利用了模拟技术. 在数字电子计算机被发展之前,模拟计算机一直使用.在模拟计算机中,微分方程里的未知量被用电信号来模拟. 这些信号被用电子的方法积分,比例变换和求和以获得方程的解,比起解析或数值运算的求解方法要容易一些. 3.1.2 本章的主要内容模拟技术广泛地运用频域的观点.我们首先扩大我们的频域的概念包括周期,非周期和随机信号. 我们将看到大多数模拟信号和过程可以被表示为频域. 我们将介绍频谱的概念, 也就是,用同时存在的很多频率来表达一个信号.带宽(频宽)(频谱的宽度) 在频域上将与时间域上的信息率有关. 频域的这个被阐述的概念也帮助我们区分线和非线性的模拟设备的影响. 线性电路被显示有"滤波器" 的能力而不需要频率组件.对比起来,新频率可以被象二极管和晶体管那样的非线性的设备产生.这种性能允许我们通过调幅和调频调制技术在频域上转换模拟信号, 这种调制技术已被公开广泛地使用公用和私人通信系统. 作为一个例子我们将描述一台调幅收音机的操作. 下面我们研究一下反馈的概念, 在模拟系统中通过反馈可以交换到象线性或者更宽的带宽那样合乎需要的质量. 如果没有反馈, 象音频放大器或者电视接收机那样的模拟系统最多提供了一个糟糕的性能. 理解反馈的好处可以提供正确评价模拟电子中运算放大器的很多用途的基础(提高对模拟电子中运算放大器的很多用途的认识) . 运算放大器(简写OP amps) 是模拟电路的基本组成部分,正如NOR 或非和NAND 与非门电路是数字电路的基本单元一样. 我们将介绍一些运算放大器一般应用, 以在模拟计算机里的他们的用途来结束. 3.2 运算放大器电路3.2.1 介绍(1) 运算放大器的重要性.运算放大器是一个在受负反馈控制的高增益的电子放大器,用来在模拟电路中完成很多运算功能.这样的放大器最初被发展完成运算,例如在模拟计算机里为微分方程的求解的积分和求和. 运算放大器的应用被增加了, 直到目前为止, 大多数模拟电子电路基于运算放大器技术.例如,你需要一个放大器获得10 倍的增益,便利, 可靠性, 费用考虑将确定使用一个运算放大器. 因此, 运算放大器形成模拟电路的基本构件, 正如NOR 或非和NAND 与非门电路是数字电路的基本单元一样. (2) 运算放大器模型典型的特性.典型的运算放大器是利用十多个晶体管,几个二极管和很多电阻器的一个复杂的晶体管放大器. 这样的放大器被在半导体芯片上批量生产并且售价少于 1 美元一个.这些部件是可靠,耐用的,并且在他们的电子特性接近理想. 图 3.2 显示一台运算放大器的基本特性和符号.有两个输入电压u+和u _ ,用大的电压增益差分放大, 通常达105 - 106. 输入电阻R 也很大, K -100 M 欧. 100 输出电阻Ro 很小, 10-100 欧. 放大器经常用正极(+ Ucc) 和负极(-Ucc) 电源提供直流电源. 对这个情况来说,输出电压在供电电压之间,- Ucc<Uo<+ Ucc. 有时一个电源接地( 即,"-Ucc" =0). 这样的话输出电压在0<Uo<+ Ucc 之间.电源连接很少被画进电路图,可以认为运算放大器和合适的电源连结起来.因此运算放大器接近一个理想的电压放大器,有高的输入电阻,低的输出抵抗和高的增益. 高增益通过使用强大的负反馈变为其他有用的特征.负反馈的全部好处被运算放大器电路利用了. 对那些早在这章里列举, 我们将为运算放大器电路还增加 3 个好处: 低扩张性, 便于设计,和简单的构造. (3) 这节的内容.我们首先分析两个普通运算放大器应用,反相和同相放大器.我们通过一个简单而有效对任何运算放大器电路使用的一种方法,推导出这些放大器的增益. 我们然后讨论有源滤波器.这是有(带了)增加了频率响应的电容器的运算放大器.然后我们简单讨论模拟计算机,以讨论运算放大器的一些非线性的应用来结束. 3.2.2 运算放大器(1) 反相放大器. 反相放大器,用图 3.3 显示,使用一个运算放大器和两个电阻. 运算放大器的输入是地(零信号) ; 负(-) 电源连接输入信号(通过Ri) 并且(通过RF) 反馈到输出信号.在下列讨论中容易混淆的是我们必须同时谈到两个放大器.运算放大器是在负反馈放大器里形成放大要素的一种放大器, 负反馈放大器包含运算放大器加上相关电阻. 为了减少混乱,我们保留术语" 放大器" 只用在反馈放大器的总体上.运算放大器绝不是一个放大器;而被叫为运算放大器.例如,如果我们对放大器提及输入电流,我们指通过R1 的电流,并非进运算放大器的电流. 我们在图里能求出 3.3 反相放大器的增益,通过求解基本的电路法则(KCL 和KVL) 或者通过试图把电路分成主要放大器和反馈系统模块.不过,我们将提出另一方法,这种方法基于运算放大器增益很高,接近无限.在如下内容里,我们将给一般的假设,这可提供给任何运算放大器电路;然后我们将把特定假设用于目前的电路.因此,我们将建立反相放大器的增益和输入电阻. (1) 我们假定输出表现良好不试图达到无限.因此我们假定负反馈使放大器稳定, 因此适度的输入电压产生适度的输出电压.如果电源是+ 10 和-10 V,例如,那些输出必须位于这些有限值之间. (2)因此,运算放大器的输入电压非常小,基本上零,因为它是输出电压除以运算放大器的大的电压增益U+-U _ =0 = 》U+= U _ 例如,如果lUol<10 V 并且A= l05, 然后我u+ u _ l<10 /lOs = 100 UV. 因此对任何运算放大器电路通常u + 和u _ 在100 uV 或更少内相等. 对在图3.3 的反相放大器来说, u+接地; 因此,u _ =0. 从而,放大器的输入电流将为Ui-u _ Ui 见(3.1) il = Ri ~ R 1 (3) 因为u+=u _ 并且Ri 很大,进入放大器的+极和-极的运算放大器的输入电流将非常小,基本上零见(3.2) 例如, Ri = 100 k, {i _ }<10-4 /lOs = 10-9 A. 对于反相放大器,公式(3.2) 暗示输入端的电流I 流过RF, 如图。
汽车专业英语全文翻译
汽车工程专业英语全文翻译一当今的汽车一般都由15000 多个分散、独立且相互配合的零部件组成。
这些零部件主要分为四类：车身、发动机、底盘和电气设备。
Body：车身Engine：发动机Brakes：制动器Power train ：传动系Steering：转向系Electrical：电器及电子设备Suspension：悬架Layout of a passenger car：乘用车总布置：商用车总布置Layout of a commercialvehicle1.1 车身汽车车身是由车窗、车门、发动机罩和行李箱盖焊接在金属板外壳发动机发动机作为动力装置。
最常见的发动机气缸的排列方式称为发动机配置。
直列式发动机的汽缸呈一列布置。
这个设计创造了一个简单的发动机缸体铸造。
在车辆应用中，汽缸数一般是2-6 缸，汽缸中心线与水平面垂直。
当汽缸数增多时，发动机尺寸和曲轴就成为一个问题。
解决这个问题的办法就是采用V 形（汽缸呈两列布置，且两列气缸之间夹角为V 形）发动机。
这个设计使发动机尺寸和曲轴都变得更短且更坚硬。
前置发动机纵向安装，既可前轮驱动也可后轮驱动。
后置发动机是将发动机安装在后轮后面。
发动机可横置或纵置，一般情况下为后轮驱动。
1.4 电气系统电气系统为起动机、点火系统、照明灯具、取暖器提供电能。
该电平由一个充电电路维护。
1.4.1 充电充电系统为所有汽车电子元件提供电能。
充电系统主要包括：蓄电池，交流发电机，电压调节器，即通常是交流发电机上不可或缺的，充电警告或指示灯和金属丝连成一个完整电路。
蓄电池为起动提供电能 ,然后发动机工作，交流发电机就为所有的电子元件提供电能。
同时也给蓄电池充电即用来使发动机起动。
电压调节器有过充保护作用。
1.4.2 起动起动系统包括：蓄电池、电缆、起动机、飞轮和换向器。
起动时，有两个动作同时运行，该起动机齿轮与飞轮齿圈啮合，并起动电机，然后运行传输到发动机曲轴。
起动机电机将起动机安装在发动机缸体上并由电池供电。
自动化专业英语第三版王树青第一章翻译
自动化专业英语第三版1.1 介绍过程控制1.近年来，对过程系统的性能改善需求变得越来越困难. 更为激烈的竞争，更加严格的环境和安全规范，以及快速变化的经济条件都是加强工厂产品质量规范的关键因素2.更为复杂的情况是，由于现代制造业朝着规模更大,集成度更高的方向发展,而使不同的加工环节之间的协调能力更低, 所以加工过程更难控制.在这种工厂中，要想让一个生产环节出现的问题不对其相连的另一个生产环节产生影响,几乎是不可能的.3.近年来，考虑到工业制造逐渐加强的安全、高效需求，过程控制这个课题变得越来越受重视.实际上，对于大多数现代工业，要满足安全、高效，产品质量的要求，没有控制系统是不可能的.1.1.1说明性的例子1.图1.1.1 所示的连续加热搅拌器可以作为过程控制的典型例子.输入液态流体的质量流量率为w，温度为Ti. 槽内成分搅拌均匀，并且用电加热器，功率为Q瓦特.2.假设输入和输出流量率是相等的，并且液体密度保持恒定，也就是说温度变化足够小，密度对温度的影响可以忽略不计. 在这些条件下，槽内液体的体积保持恒定3.加热搅拌器的控制目标是保持输出温度T在一个恒定参考值TR上.参考值在控制术语中指的是给定值. 下面我们考虑两个问题.把加热搅拌器内的液体从输入温度Ti加热到输出温度TR，需要多少热量？1.要确定达到设计运行条件下的热量需求，我们需要写下槽内液体的稳定能量平衡式.在写平衡式之前，假设槽内是完美搅拌的，同时忽略热损耗.2.在这些条件下，槽内成分的温度保持一致，因此，输出温度等于槽内液体温度..3.分别表示Ti, T, w, 和 QC 是液体的比热. 我们假设C是恒定的. 在设计条件下，将其代入方程（1），1.方程（2）是加热器的设计方程.如果我们的假设是正确的，同时输入流量和输入温度等于他们的标定值，那么有方程（2）给出的输入热量将使输出温度保持在期望值TR.但是，如果给定条件变化，会产生什么样的结果呢？这给我们带来第二个问题：2.问题2. 假设输入温度Ti随时间变化. 我们如何确保温度T保持或靠近给定值TR？最为一个特殊的例子，假设Ti增加到一个大于的值. 如果Q保持在标定值上恒定，我们可以得到输出温度将增加，因此T>TR.为应付这种情况，有一些可能的策略控制出口温度T方法1。
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1.1We have learned that all computers have similar capabilities and perform essentially the same functions, although some might be faster than others. We have also learned that a computer system has input, output, storage, and processing components; that the processor is the “intelligence” of a computer system; and that a single computer system may have several processors. We have discussed how data are represented inside a computer system in electronic states called bits. We are now ready to expose the inner workings of the nucleus of the computer system — the processor.我们已经知道，所有的计算机都具有相似的能力，并且在本质上执行相同的功能，尽管一些可能会比另一些快一点。
我们也知道，一个计算机系统具有输入，输出，存储和处理部件；处理器是一个计算机系统智能核心，并且一个计算机系统可以有许多个处理器。
我们已经讨论过如何在计算机系统内部，用被称作“位”的电子状态来表现数据，现在我们要弄明白计算机系统的核心，即处理器，的内在的工作方式。
The internal operation of a computer is interesting, but there really is no mystery to it. The mystery is in the minds of those who listen to hearsay and believe science-fiction writer. The computer is a nonthinking electronic device that has to be plugged into an electrical power source, just like a toaster or a lamp. 计算机的内部操作很有意思，但确实没有什么神秘可言。
所谓的神秘只是存在于那些听信传闻和相信科幻小说作家的人的意识中。
计算机就是一种没有思想的需要接通电源的电子设备而已，与烤面包机和台灯差不多。
Literally hundreds of different types of computers are marketed by scores of manufacturers [1]. The complexity of each type may vary considerably, but in the end each processor, sometimes called the central processing unit or CPU, has only two fundamental sections: the control unit and the arithmetic and logic unit. Primary storage also plays an integral part in the internal operation of a processor. These three — primary storage, the control unit, and the arithmetic and logic unit —work together. Let’s look at their functions and the relationships between them.不加夸张地讲，市场上有几百种不同类型的计算机在销售.每种电脑在复杂性上可能有很大区别，但归根结底,每种处理器，有时称为中央处理器即cpu，只有两个基本部分:控制单元和计算逻辑单元.主内存在处理器内部操作中也是一个不可缺少的部分.这三个部件--主内存，控制单元和计算逻辑单元--一起工作.然我们看看它们(各自的)功能和它们之间的联系。
Unlike magnetic secondary storage devices, such as tape and disk, primary storage has no moving parts. With no mechanical movement, data can be accessed from primary storage at electronic speeds, or close to the speed of light. Most of today’s computers use DRAM (Dynamic Random-Access Memory) technology for primary storage.A state-of-the-art DRAM chip about one eighth the size of a postage stamp can store about 256,000,000 bits, or over 25,600,000 characters of data!主存与其他的辅助存储器（如：磁带、硬盘）不一样的是，主存不含有运转部件。
由于没有机械运转的需要，主存种数据访问可以达到电子的速度，或接近于光速。
当今计算机的主存大多数使用DRAM（动态随机存取存储器）技术。
目前最新的工艺水平是：一块只有大约1/8张邮票大小的DRAM芯片却可以存储大约256,000,000位，约25,6000,000个字符的数据。
Primary storage, or main memory, provides the processor with temporary storage for programs and data. All programs and data must be transferred to primary storage from an input device (such as a VDT) or from secondary storage (such as a disk) before programs can be executed or data can be processed. Primary storage space is always at a premium; therefore, after a program has been executed, the storage space it occupied is reallocated to another program awaiting execution.主存储器，也就是说内存，用于为处理器暂时存放程序和数据。
所有的程序和数据在被操作之前必须从输入设备（如VDT）或者辅助存储器转存到主存储器中。
主存储器存储容量通常是相当有限的，因此，在一个程序执行结束，它所占用的存储空间必须被重新分配给其它正在等待执行操作的程序。
Figure 1-1 illustrates how all input/output (I/O) is “read to” or “written from” primary storage. In the figure, an inquiry (input) is made on a VDT. The inquiry, in the form of a message, is routed to primary storage over a channel (such as a coaxial cable). The message is interpreted, and the processor initiates action to retrieve the appropriate program and data from secondary storage [3].The program and data are “loaded”, or moves, to primary storage from secondary storage. This is a nondestructive read process. That is, the program and data that are read reside in both primary storage (temporarily) and secondary storage (permanently). The data are manipulated according to program instructions, and a report is written from primary storage to a printer.图 1-1描述了输入/输出设备与主存储器间的读和写过程。
在图中，VDT发出一个输入请求，请求是以消息模式通过通道（如同轴电缆）发送到主存储器。
这个查询被解释，处理器发起操作从辅助存储器中调用合适的程序和数据。
程序和数据从辅助存储器传送到主存储器中，这是一个非破坏性的读取过程，也就是说，程序和数据同时存在于主存（临时保存）和辅助存储器（永久保存）中。
根据程序指令的指示，处理器对数据进行操作，并从主存传送一份报告到打印机。
A program instruction or a piece of data is stored in a specific primary storage location called an address. Addresses permit program instructions and data to be located, accessed, and processed. The content of each address is constantly changing as different programs are executed and new data are processed.程序指令和数据是存储在主存中一个特殊的位置，称为地址空间。