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单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,学习重点：,（1）掌握有关电源的基本单词、词组和缩略语的基本含义及用法,（2）培养阅读翻译有关电源科技文献和产品说明书的能力,（3）学习科技英语中的名词化结构，掌握由动词、形容词、过去分词、动名词等派生或转化来的抽象名词,2 Power Supplies,生词,bypass ,bai.p:s,n.,支路，道,coil,kil,n.,卷，线圈,discharge,dist:d,v.&n.,放电,Passage A,Basics of Power Supply,filter filt n.滤波器，过滤器 v.过滤,heatsink hi:t sik n.散热器,magnetic mgnetik a.磁的,mains mein n.电网,outlet autlet n.电源插座,passive psiv a.被动的,消极的；无源的,pulsating plstia.脉动的,rated reitid a.标称的,ripple ripl n.纹波,sample smpln.样品；标本v.抽取样品,smooth smu:a.平稳的，流畅的 v.使.光滑，滤波,transformer trnsf:m(r),tr:-n.变压器,bridge rectifier 桥式整流器,magnetic field.磁场,overheating 过热,Pulse Width Modulated(PWM)Regulator 脉冲宽调制调节器,Pulse Rate Modulated(PRM)Regulator 脉冲速率调节器,RMS(=Root-Mean-Square)均方根,2.课文翻译讲解,When,working with electronics,you always need power supply,a device that transfers electric power from a source to a load using electronic circuits,.,现在分词短语，作时间状语,同位语，进一步说明power supply,翻译：,当你工作中用到电子学时,，你就需要电源装置。电源是一,用电路把电能从电源输送给负载,的设备。,A typical,application of,power supplies is,to convert utilitys AC input power into regulated DC voltage(s),required for electronic equipment,.Depending on the mode of operation of power semiconductors power supply can be linear or switching.,Application是动词转化,过来的名词,不定式短语作表语,过去分词短语,，,修饰,DC voltage(s）,翻译：,电源的主要用途是将有效的,交流输入功率转换为电子设备所需,的直流电压。根据电源功率半导体,器件的工作方式电源装置可以是线,性或开关式的。,Linear voltage power supplies are commonly used for both step-up(output supply voltage is greater than input source voltage)and step-down(output supply voltage is lower than input source voltage)applications.Linear power supplies are also available with either a fixed output voltage or a variable output voltage when,using external biasing,.,翻译：,线性稳压器常用于电压的提升（输出供电电压大于输入源电压）,和降低（输出供电电压低于输入源电压）。使用外部偏置，线性稳压,器也可产生恒定输出电压或可变输出电压。,The basic block of a linear power supply is shown in Figure 2-1,which includes:Transformer,which steps down high voltage AC mains to low voltage AC;Rectifier,which converts AC to DC,but the DC output is varying;Filtering,which filters the DC from varying greatly to a small ripple;Regulator,which eliminates ripple by setting DC output to a fixed voltage.,翻译：,线性电源可以分解为一系列基本模块，如图2-1所示，该图包括：变,压器把电网高压交流电转换为低压交流电；整流器把交流电转换为,直流电，但是直流输出是变化的；滤波器从直流电流中滤掉变化较大的,成分使之仅有小的纹波成分；稳压器消除纹波，输出固定值的直流电压,。,Transformer converts the voltage from the wall outlet(mains)to a different,usually a lower voltage.The input coil is called the primary and the output coil is called the secondary.There is no electrical connection between the two coils;instead they are linked by an,alternating magnetic field,created in the soft-iron core of the transformer.,翻译：,当一个小的电压V正向加到二极管时，,就会有一个小的电流流过，并产生一个大约,为0.6V到1V的电压降,Von,，这常被认为是二,极管的“正向电压降”，若为硅二极管，,大约为0.7V。,alternating magnetic field为动名词短语,A bridge rectifier circuit is employed to produce DC output and can be made by four individual diodes or a single chip,on which an array of four diodes is integrated,for full wave,rectification,and also can be made by a single diode yielding a half wave(,pulsating,)output.1.4V is used up in the bridge rectifier because each diode uses 0.7V when conducting and there are always two diodes,conducting,.,翻译：,桥式整流器线路用,于产生直流输出，它可以,由四个单个的二极管或集,成有四个二极管的单个芯,片构成以用于全波整流，,也可用产生半波（脉冲）,输出的一个二极管构成。,1.4伏电压被消耗在桥式,整流器中，因为在导通时,每个二极管用掉0.7伏，,而在在桥式整流器中总是,有两个二极管同时导,通。,rectification,是由动词,转化来的抽象名词,，,pulsating 和,conducting,为动词转化来的动名词,Bridge rectifiers are rated by the passed maximum current and the maximum reverse voltage they can withstand(this must be at least three times the supply RMS voltage so the rectifier can withstand the peak voltages).,翻译：,桥式整流器是由它能通过的最大电流值和所能承受的最大反向电压,（这一电压值至少是均方根电压的三倍，这样整流器才能承受住峰值电压,）来标称的,。,A filter,consisted of capacitors or resistors or inducers or their,combination,s,is used to filter part of the pulses giving a smoothed DC voltage.However,filtering,is not perfect and small pulses,known as ripple,are still remained.For many circuits a ripple,which is 10%of the supply voltage,is satisfactory.,翻译：,由电容器，或电阻,器，或电感器，或它们的组,合而构成的滤波器可过滤部,分脉冲而得到平滑的直流电,压。然而，滤波器不是完美,的，仍然存在小脉冲，常称,之为纹波电压。对于许多电,路来说，纹波电压大小为电,源电压的10是合适的。,combination,是由动词转化来,的抽象名词,，,filtering,为动词,转化来的动名词,A simple voltage regulator for low current power supplies can,be made up of,a resistor and a Zener diode connected in reverse.But nowadays,many types of voltage regulator ICs can be available with fixed(typically 5,12 and 15V)or variable output voltages,largely simplifying the regulator designs.Most regulators include some automatic,protection,from excessive current(overload protection)and,overheating,(thermal protection).,翻译：,用于低电流电源，稳压器可以简单地由一个电阻和一个反向连接的齐,纳二极管构成。但是目前，许多类型的集成稳压器的输出可以为固定值（通,常为5伏，12伏和15伏）或可变值，大大简化了设计过程。大部分稳压器都,具有一些过电流(过载保护)和过热（热保护）自动保护功能。,Many of the fixed voltage regulator ICs has 3 leads and look like power transistors,such as the 7805+5V 1A regulator.They include a hole for attaching a heatsink,if necessary.,The advantage of linear regulators is simple,implementation,and,minimal parts(just the IC in the case of fixed output)and low output ripple.The maj
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