外文翻譯--led是如何工作的

1、<p><b>　　英文原文</b></p><p>　　How Light Emitting Diodes Work</p><p>　　Light emitting diodes, commonly called LEDs, are real unsung heroes in the electronics world. They do dozens o

2、f different jobs and are found in all kinds of devices. Among other things, they form the numbers on digital clocks, transmit information from remote controls, light up watches and tell you when your appliances are turne

3、d on. Collected together, they can form images on a jumbo television screen or illuminate a traffic light. Basically, LEDs are just tiny light bulbs that fit easily into </p><p>　　What is a Diode? A diode is

4、 the simplest sort of semiconductor device. Broadly speaking, a semiconductor is a material with a varying ability to conduct electrical current. Most semiconductors are made of a poor conductor that has had impurities (

5、atoms of another material) added to it. The process of adding impurities is called doping. In the case of LEDs, the conductor material is typically aluminum-gallium-arsenide. In pure aluminum-gallium-arsenide, all of the

6、 atoms bond perfectly to their ne</p><p>　　How Can a Diode Produce Light? Light is a form of energy that can be released by an atom. It is made up of many small particle-like packets that have energy. These

7、particles, called photons, are the most basic units of light. Photons are released as a result of moving electrons. In an atom, electrons move in orbitals around the nucleus. Electrons in different orbitals have differen

8、t amounts of energy. Generally speaking, electrons with greater energy move in orbitals farther away from the nucleu</p><p>　　LEDs have several advantages over conventional incandescent lamps. For one thing,

9、 they don't have a filament that will burn out, so they last much longer. Additionally, their small plastic bulb makes them a lot more durable. They also fit more easily into modern electronic circuits. But the main

10、advantage is efficiency. In conventional incandescent bulbs, the light-production process involves generating a lot of heat. This is completely wasted energy, unless you're using the lamp as a heater. LE</p>&

11、lt;p>　　TRANSIENT VOLTAGE SUPPRESSOR(TVS) Diode PRESENTATION</p><p>　　? High protection on sensitive mobile electronic devices</p><p>　　? Follow strictly to the IEC 61000-4-2 ESD test standard

12、</p><p>　　? Using the behavior of diode P/N junction to achieve ESD protection</p><p>　　What are Transient Voltages?</p><p>　　? These are faults which cause the voltage to go outsid

13、e normal limits for a period of time. Transient voltages are characterized by three things: </p><p>　　VeryHigh Voltage, Occur For A Very Short Period of time (in nanoseconds) and High Occurrence. Many trans

14、ients cause damage to micro-semiconductor chipsets by degra ding their performance. This damage is cumulative and eventually reaches apoint where sudden and complete failure of the component results. Moreover, some tran

15、sients are capable of causing immediate equipment failures. Equipment failures caused by transients are hard to detect and are often incorrectly blamed on other ‘perceived’ cau</p><p>　　TVS diode’s Advantage

16、s</p><p>　　? TVS Diode vs. Zener Diode</p><p>　　Compared with the traditional Zener diode, TVS diode has a larger P/N cross section. TVS diode component is constructed and designed to absorb lar

17、ger amounts of energy, joules, with a faster response time than Zener diode. Zener diode has a higher clamping voltage and heat dissipation is slower.</p><p>　　? TVS Diode vs. Multilayer Metal oxide Varistor

18、, MLV</p><p>　　A major difference between TVS diode and MLV is, as MLV absorbs transient energy, its electrical parameters such as Leakage current and Breakdown voltage tend to drift away from their original

19、 specifications which exhibits an inherent wear out mechanism within the structure. Because of its high impedance, its clamping ratio can</p><p>　　reach as high as 3. Therefore MLV is more suitable to be app

20、lied on less sensitive lines where its high clamping voltage can be tolerated.</p><p>　　? TVS Diode vs. Ceramic Capacitor</p><p>　　Ceramic capacitor is not able to withstand a high transient vol

21、tage. A 10kV transient voltage will destroy about 60% of the component of the ceramic capacitor while TVS diode is able to withstand up to 15Kv transient voltage. Ceramic capacitor is also not able to dissipate heat effi

22、ciently like what TVS diode does when transient occurs.</p><p>　　? TVS Diode vs. Gas Discharge Tubes, GDTs</p><p>　　TVS diode limits voltage spike to acceptable level by clampingwhile GDT limits

23、 voltage spike by crowbar action. GDT conducts when its threshold voltage is exceeded and then trigger to an on-state voltage of only a few volts. A drawback of GDT protection is that the trigger on state voltage is belo

24、w the operating voltage of the protected load. The protected load will be shut down temporarily.</p><p><b>　　LED是如何工作的</b></p><p>　　通常被稱為LED的發(fā)光二極管，使電子世界中真正的無名英雄。LED的功能多達幾十種，被廣泛的應用于各種

25、裝置之中。在其他應用場合，LED可以作為數(shù)字鐘的數(shù)碼顯示、傳送來自遙控裝置的數(shù)據(jù)、手表的背光燈以及指示各種器械何時開啟。歸納起來，LED可以在巨大的電視熒屏上形成各種圖像或者點亮交通燈。從本質(zhì)上講，LED就是一些小燈泡，所以很適合用于電子線路中。但與普通白熾燈泡不同的是，LED沒有能燒盡的燈絲，而且使用過程中也不會變得很熱。它們僅僅依靠半導體材料的電子運動來發(fā)光照明，并且其壽命和標準晶體管的一樣長。在這篇文章里，我們將一起來探究一下這些

26、普遍存在的有色眼鏡后面的簡單原則，對于揭示該過程中電氣光學方面的潛規(guī)則具有一定的啟發(fā)。</p><p>　　那么什么是二極管呢？二極管是最簡單的一種半導體元件。一般來說，半導體是在電流傳導方面特性不唯一的一種材料。多數(shù)半導體是由內(nèi)含雜質(zhì)（其他材料的原子）的導體制成的。添加雜質(zhì)的過程被稱為摻雜。在LED中，傳導材料通常選用鋁—鎵—砷化物（AIGaAs）。在純凈的鋁—鎵—砷化物中，所有的原子和相鄰原子間都非常完美地結

27、合在一起，沒有能自由運動的電子（帶負電的粒子）傳導電流。在摻雜過的材料中，添加的原子改變了原有的平衡，產(chǎn)生了自由電子或空穴。增加的這兩種粒子都能增強該材料的傳導性。因為電子帶負電，故有多余電子的半導體被稱為N型半導體。在N型半導體中，自由電子從負電區(qū)域移向正電區(qū)域。因為空穴帶正電，故有多余空穴的半導體被稱為P型半導體。電子可以在兩個空穴之間來回移動，從負電區(qū)域移向正電區(qū)域。這樣，從表面上看空穴是從正電區(qū)域移向負電區(qū)域。二極管是由制作在同

28、一硅片上的P型半導體和N型半導體所組成，電極在兩端引出。這種制作工藝使得二極管具有單向?qū)щ娦浴６O管兩端不加電壓是，N區(qū)的自由電子和P區(qū)的空穴在兩層的結合處進行復合形成耗盡層。在耗盡層中，半導體材料還原為絕緣狀態(tài)—所有的空穴都和電子發(fā)生復合，所以沒有自</p><p>　　二極管是怎樣發(fā)光的呢？光是原子釋放能量的一種形式。光有許多像存有能量的包裹一樣的小微粒組成。這些微粒被稱為光子，是光的基本單元。光子由移動的電

29、子所釋放。在一個原子中，電子沿特定的軌跡繞原子核作圓周運動。處于不同軌道的電子所含能量有所不同。一般而言，具有較高能量的電子在離核較遠的軌道中運行。如果一個電子從低軌道進入高軌道，則一定有外界因素促使其能級發(fā)生變化。相反，電子從高軌道躍遷到低軌道時會釋放能量。這種能量是以光子的形式釋放出來的。能級差越大，躍遷時釋放的光子能量越高，即頻率越高。正如前面一段提及的那樣，穿越二極管的自由電子能進入P區(qū)的空穴。這相當于一個微粒從傳送通道落入較低

30、的軌道，所以電子以光子的形式釋放能量。事實上，任何二極管都存在這種現(xiàn)象，但只有特殊材料制成的二極管才能發(fā)出可見光。比如，在一個標準硅二極管中的原子按某種方式方式排列起來，這種方式使得電子躍遷的距離相對較短。結果，光子的頻率就很低以至于人眼無法看到，這種頻率的光子處于光譜中的紅外線區(qū)域。當然，這未必很糟糕：和其他元器件相比，紅外LED是遙控裝置的首選。用于數(shù)字鐘的數(shù)碼顯示的能發(fā)出可見光的二極管是由一種特殊材料制成，其</p>

31、<p>　　同傳統(tǒng)的白熾燈相比，LED有以下幾點優(yōu)勢。首先，LED內(nèi)沒有回燒盡的燈絲，所以其壽命要長得多。其次，小體塑膠球形封裝使LED更耐用。對于傳統(tǒng)的白熾燈而言，在其工作過程中會產(chǎn)生大量的熱。這完全是一種能源浪費，除非你想用燈泡作發(fā)熱器。相對而言，LED產(chǎn)生的熱量非常少。大部分電功率將直接用于發(fā)光，這在很大程度上降低了電力需求。以前，LED的成本較高以至于無法將其廣泛地用于照明。但在過去的十年里，半導體元件的成本急劇下降

32、，使得LED在許多情況之下的照明元件選擇上很劃算。雖然到現(xiàn)在為止，LED的造價仍比白熾燈的高，但從長遠來看其應用前景非常廣闊。在不久的將來，LED會在技術領域里發(fā)揮更大的作用。</p><p>　　瞬態(tài)電壓抑制二極管介紹</p><p>　　? 有效保護高感應可攜式設備</p><p>　　? 根據(jù)及通過IEC國際靜電測試標淮</p><p>

33、;　　? 應用二極管P/N結面的特性來達到靜電保護原理</p><p><b>　　什么是瞬態(tài)電壓?</b></p><p>　　瞬態(tài)電壓是交流電路上電流與電壓的一種瞬時態(tài)的畸變。浪涌、諧波為主要的表現(xiàn)形式。瞬態(tài)電壓最主要的特點有三個: </p><p>　　超高壓, 瞬時態(tài), 高頻次。超高壓是指通常的瞬態(tài)電壓尖峰，高出正常電路電壓幅值的好幾倍

34、。瞬時態(tài)是指瞬態(tài)電壓持續(xù)的時間非常之短，它可以在數(shù)億分之一秒內(nèi)完成迸發(fā)到消失的過程。高頻次是指瞬態(tài)電壓的活動十分頻繁，可以說無時不有、無處不在。瞬態(tài)電壓是會對微電子半導體芯片造成損壞的。雖然有些微電子半導體芯片受到瞬態(tài)電壓侵襲后,它的性能沒有明顯的下降，但是多次累積的侵襲會給芯片器件造成內(nèi)傷而形成隱患。瞬態(tài)電壓對芯片器件造成的損傷難以與其它原因造成的損傷加以區(qū)別, 從而不自覺地掩蓋了失效的真正原因。由于微電子半導體芯片的精、細、結構,

35、如要替換或修理需要使用高度精密儀器,是非常費財?shù)?。為一的有效方法就是把瞬態(tài)電壓抑制在被保護元件能承受的安全水平。</p><p>　　瞬態(tài)電壓抑制二極管的優(yōu)勢</p><p>　　? 瞬態(tài)電壓抑制二極管與齊納二極管</p><p>　　與傳統(tǒng)的齊納二極管相較,瞬態(tài)電壓抑制二極管的P/N結面積更大。這一結構上的改進使瞬態(tài)電壓抑制二極管具更強的高壓承受力和更快的效率。相

36、較之下齊納二極管也有較高的抑制電壓和較慢的散熱速度。</p><p>　　? 瞬態(tài)電壓抑制二極管與多層金屬氧化物突波吸收器</p><p>　　瞬態(tài)電壓抑制二極管與多層金屬氧化物突波吸收器最大的不同是多層金屬氧化物突波吸收器的功能會在瞬態(tài)電壓的沖擊下衰退。當瞬態(tài)電壓侵襲時,多層金屬氧化物突波吸收器的相關參數(shù)如漏電電流值和中止電壓值都會偏離原來的參數(shù)而變得不準確。還有多層金屬氧化物突波吸收器

37、有較高的阻抗所以它的抑制電壓可達最初中止電壓的3倍,這種特性只適合用于對電壓不太感應的線路和元件的保護。</p><p>　　? 瞬態(tài)電壓抑制二極管與陶瓷電容器</p><p>　　陶瓷電容器這類元件對高壓的承受力比較弱。如有10kV的瞬態(tài)電壓沖擊時,會對陶瓷電容器造成約60%的損壞,而瞬態(tài)電壓抑制二極管能承受到15kV的瞬態(tài)電壓。在瞬態(tài)電壓侵襲時所產(chǎn)生的熱量,陶瓷電容器也沒有辦法象瞬態(tài)電