电子信息与通信工程专业英语王立琦版课文翻译.doc

Resistor
A resistor is a two-terminal electronic component that opposes an electric current by producing a voltage drop between its terminals in proportion to the current， that is ,in accordance with Ohm’s law ：V=IR .The electrical resistance R is equal to the voltage drop V across the resistor divided by the current I through the resistor。 Resistors are used as part of electrical networks and electronic circuits.
电阻器是一个二端口电子元件,电阻是阻止电流流动，通过按比例产生其端子之间的电压降的电流,也就是说，根据欧姆定律:V = IR.电阻R等于电压降V除以通过电阻的电流I。电阻作为电子网络和电子电路的一部分。
Transistor
In electronics, a transistor is a semiconductor device commonly used to amplify or switch electronic signals 。 A transistor is made of a solid piece of a semiconductor material , with at least three terminals for connection to an external circuit。 A voltage or current applied to one pair of the transistor’s terminals changes the current flowing through another pair of terminals。 Because the controlled current can be much larger than the controlling current, the transistor provides amplification of a signal。 The transistor is the fundamental building block of modern electronic devices， and is used in radio， telephone, computer and other electronic systems。 Some transistors are packaged individually but most are found in integrated circuits.
在电子技术中，晶体管是一种，常用来放大或进行开关控制电子信号的半导体器。晶体管是由一块固体半导体材料制成的，且至少有三个终端与外部电路连接。电压或电流适用于一双晶体管的终端改变目前流经的另一对终端.因为受控电流可以远大于控制电流，晶体管提供信号的放大。晶体管是构建现代电子设备的基本单元,并在收音机，电话，计算机和其它电子系统被使用.一些晶体管被单独包装，但大多数都在集成电路中。
Transformer
A transformer is a device that transfers electrical energy from one circuit to anther through inductively coupled electrical conductors . A changing current in the first circuit creates a changing magnetic field； in turn， this magnetic field induces a changing voltage in the second circuit。 By adding a load to the secondary circuit， one can make current flow in the transformer， thus transferring energy from one circuit to the other。
变压器是一种通过感应耦合将电能从一个电路传输到另一个电路的装置。在第一电路中的一个变化的电流创建一个不断变化的磁场；反过来，这个磁场诱导第二个电路中的电压变化.通过向二次回路中增加负载，使电流在变压器中流动，从而将能量从一个电路传递到另一个电路中。
Relay
A relay is an electrical switch that opens and closes under the control of another electrical circuit . In the original form ,the switch is operated by an electromagnet to open or close one or many sets of contacts。 It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit ，it can be considered to be, in a broad sense, a form of an electrical amplifier。
继电器是一种电子开关，控制另一个电路的打开和关闭。在原始形式中，该开关是由一个电磁铁操作，打开或关闭一个或多个触点.它是由约瑟夫亨利在1835年发明的。由于继电器能够控制比输入电路功率更高的输出电路，广义上说， 它可以被认为是电子放大器的一种形式。
Types of circuits
In any circuit where the only opposition to the flow of electrons is resistance ， there is a definite relationship between the values of voltage ， current， and resistance。 This relationship was discovered by George Simon Ohm in 1827. It is known as Ohm’s law。
任何电路中电阻仅仅阻止电子的流动, 电压，电流和电阻的值之间有一个明确关系.这种关系在1827年由格奥尔格·西蒙·欧姆发现。它被称为欧姆定律。
Duality
Because of the strong similarity between the Fourier analysis and synthesis equations in continuous time , there is a duality between the time domain and frequency domain . However ， for the discrete—time Fourier transforms of aperiodic signals ， no similar duality exists , since aperiodic signals and their Fourier transforms are very different kinds of functions : Aperiodic discrete—time signals are ， of course， aperiodic sequences ， while their Fourier transforms are always periodic functions of a continuous frequency variable 。
由于傅里叶分析和合成方程在在连续时间上有很大的相似性，有一个时域和频域之间的二元性。然而，对于非周期信号的离散傅里叶变换，没有类似的二元性存在, 由于非周期信号和它们的傅立叶变换有着迥然不同的功能： 当然，非周期离散时间信号,非周期序列,然而他们的傅里叶变换总是周期性的频率连续变化的函数。
Network Configuration
Broadly speaking , there are two types of network configuration based on their layout ，peer-to-peer networks and client/server network。
Peer—to-peer networks are more commonly implemented where less than ten computers are involved and where strict security is not necessary。 All computers have the same status , hence the term ”peer” ， and they communicate with each other on an equal footing 。Files ， such as word processing or spreadsheet documents ,can be shared across the network and all the computers on the network can share devices ，such as printers or scanners ,which are connected to any one computer.
广义地说，有基于两种类型网络配置的的布局，对等网络和客户机/服务器网络。
对等网络较为普遍实现，其中不到10台计算机参与并且不需要很严格的安全性。所有计算机都具有相同的地位，因此被称为“对等"，而且他们平起平坐相互通信。文件，例如文字处理或电子表格文档，可以通过网络共享来和所有的网络上的计算机进行设备共享，打印机或者扫描仪，可以连接到任何一台计算机。