回顧與復習Electrical Networks 單詞及短語中英文對譯：,rate of change of current voltage/current source in series algebraic sum amplifying device current flow differentiation with respect to time second-order,電網(wǎng)絡 無源網(wǎng)絡 有源網(wǎng)絡 回路電流 電壓降 等效電路 微分方程 回路分析法,翻譯下面一段英文 A common method of analyzing an electrical network is mesh or loop analysis. The fundamental law that is applied in this method is Kirchhoffs first law, which states that the algebraic sum of the voltage around a closed loop is 0, or, in any closed loop, the sum of the voltage rises must equal the sum of the voltage drop. Mesh analysis consists of assuming that currentstermed loop currentsflow in each loop of a network, algebraically summing the voltage drops around each loop, and setting each sum equal to 0.,科技英語語法詞類,二、介詞 1. 介詞短語在句中的主要語法功能 (1) 作狀語（句中位置靈活） e.g1: In nature there are many substances. 自然界中有許多物質(zhì)。 e.g2: Their channel resistances will be relatively low, on the order of 500 Ohms. 它們的溝道電阻相當?shù)?，大約為500歐姆。,(2) 作定語（后置定語） e.g1: There are batteries for mobile phone. 這是供手機用的電池。 e.g2: An electric switch is often on a wall near the door of a room. 開關(guān)常裝在房間門旁的墻上。 (3) 作表語（置于系動詞之后） e.g1: The supply currents specified in the data sheet are for static DC conditions only. 數(shù)據(jù)單上標明的電源電流只適用于靜態(tài)直流條件。,(4) 作補足語 e.g1: This parameter is defined as the ratio of signal to noise. 這個參數(shù)定義為信噪比。（主語補足語） e.g2: We refer to this electronic device as a robot. 我們稱這種電子設(shè)備為機器人。（賓語補足語） (5) 作插入語 如：in fact; of course; for example e.g: For example, we can make an electric bell with this kind of magnet. 例如，我們可以用這種磁鐵來制作電鈴。,2. 介詞的一些特殊用法 (1) of + 抽象n.=adj. of interest=interesting of use =useful of value =valuable of importance=important of help =helpful e.g1: Laboratory work is considered of great importance to students of engineering. 實驗對工科學生來說及其重要。,(2) with + 抽象n.=adv. with care =carefully with ease = easefully with efficiency = efficiently with skill = skillfully with difficulty=difficultly e.g: This experiment should be done with care. 這個實驗應該仔細地做。,三、數(shù)詞 1. 分數(shù)的表示法 分子（用基數(shù)詞表示）：one, two, three, , ten 分母（用序數(shù)詞表示）：first, second, third, 注：當分子=1時，分母用單數(shù)形式； 當分子1時，分母用復數(shù)形式。 e.g: 1/3 one third 2/5 two fifths,零點幾的表示法：轉(zhuǎn)化為分數(shù)表示 E.g: 0.3 3/10 three tenths 若是數(shù)值帶有單位，在分數(shù)表示后+“of a(an) +單位名稱” E.g: 0.3g three tenths of a gram,2. 特殊表示法,E.g1: The voltage is 100 times the signal applied to the amplifier. 這個電壓是加給放大器信號的100倍。（相當于在倍數(shù)詞后省略了as large as） E.g2: The force provided by two parallel rubber bands is twice that provided by one rubber band. 兩根平行的橡皮筋所提供的力為一根橡皮筋的兩倍。 E.g3：At this point, the current in the branch is ten times what it was. 這時，該支路中的電流為原來的10倍。,3.兩個典型句型 (1) “n” times +比較級+than =“n” times as +原級+as E.g: This wire is four times longer than that one. =This wire is four times as long as that one. (2) by a factor of “n” 與表示“增加”、“減少”等詞連用時應譯為“n-1”倍。 E.g: In this case, its gain will be increased by a factor of 5. 在這種情況下，其增益將提高4倍。,P1U2A The Operational Amplifier,背景知識：運算放大器是一種常用的電子器件。具有輸入阻抗高、輸出阻抗低、放大倍數(shù)大、性能穩(wěn)定的特點。在利用運算放大器設(shè)計電路時，由于其放大倍數(shù)很大，電路的特性主要是由外部輸入輸出網(wǎng)絡的特性決定，與放大器本身的特性關(guān)系不大，因此可以方便地構(gòu)成各種電子線路。,閱讀文章回答問題： What problem is usually concerned with electrical devices as amplifiers? 2. What are the advantages of operational amplifier? 3. How many characteristics are of operational amplifier? And what are they? 4. What is one of the key features of Op-Amp design? 5. What are the important laws of operational amplifier?,P1U2A The Operational Amplifier,生詞與短語： operational amplifier 運算放大器 electronic device 電子器件 depend upon 依賴于，取決于 internal property 內(nèi)部特性 parameter n. 參數(shù) vary v. 不同于 component n. 元件，成分 transistor n. 晶體管 inner working 內(nèi)部工作原理,P1U2A The Operational Amplifier,beyond the scope of 超出的范圍 a variety of 多種的，各種的 filter circuit 濾波電路 with respect to 相對于 differential device 差分裝置 KVL Kirchhoff Voltage Law 基爾霍夫電壓定律 gain factor 增益因子 denominator n. 分母 fraction n. 分數(shù) numerator n. 分子 independent of 與無關(guān),P1U2A The Operational Amplifier,難句解釋： 1 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. 對于像廣義放大器這樣的電子設(shè)備，存在的一個問題是其增益AU 或AI取決于兩端口系統(tǒng)的內(nèi)部特性。 That 作從屬連接詞，在句中沒有實在意義，只起連接從句的作用，引導主語從句、賓語從句、同位語從句或表語從句。,P1U2A The Operational Amplifier,2 Not shown are other connections necessary to run the Op-Amp such as its attachments to power supplies and to ground potential. 使運算放大器正常工作所必需的其他一些管腳連接，諸如：電源管腳和接地管腳并未畫出。 Not shown： 名詞，作為主語,P1U2A The Operational Amplifier,3 This is one of the key features of Op-Amp designthe action of the circuit on signals depends 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. 這是運算放大器設(shè)計的重要特征之一在信號作用下，電路的動作僅取決于能夠容易被設(shè)計者改變的外部元件，而不取決于運算放大器本身的細節(jié)特性。 Which 作關(guān)系代詞用，用于限制性定語從句中，專指事物而言。,P1U2A The Operational Amplifier,翻譯示例： One problem with electronic devices corresponding to the.At this point we will make no attempt to describe these inner working.,像廣義放大器這樣的電子器件存在的一個問題就是它們的增益AU或AI取決于雙端口系統(tǒng)(、、RI、Ro等)的內(nèi)部特性。器件之間參數(shù)的分散性和溫度漂移給設(shè)計工作增加了難度。,P1U2A The Operational Amplifier,設(shè)計運算放大器或Op-Amp的目的就是使它盡可能的減少對其內(nèi)部參數(shù)的依賴性、最大程度地簡化設(shè)計工作。運算放大器是一個集成電路，在它內(nèi)部有許多電阻、晶體管等元件。就此而言，我們不再描述這些元件的內(nèi)部工作原理。,P1U2A The Operational Amplifier,A totally general analysis of the Op-Amp is beyond the scope from which Op-Amp integrated circuits are constructed, will be discussed.,運算放大器的全面綜合分析超越了某些教科書的范圍。在這里我們將詳細研究一個例子，然后給出兩個運算放大器定律并說明在許多實用電路中怎樣使用這兩個定律來進行分析。這兩個定律可允許一個人在沒有詳細了解運算放大器物理特性的情況下設(shè)計各種電路。,P1U2A The Operational Amplifier,因此，運算放大器對于在不同技術(shù)領(lǐng)域中需要使用簡單放大器而不是在晶體管級做設(shè)計的研究人員來說是非常有用的。在電路和電子學教科書中，也說明了如何用運算放大器建立簡單的濾波電路。作為構(gòu)建運算放大器集成電路的積木晶體管，將在下篇課文中進行討論。,P1U2A The Operational Amplifier,The symbol used for an ideal Op-Amp is shown with respect to ground is given by the expression,理想運算放大器的符號如圖1-2A-1所示。圖中只給出三個管腳：正輸入、負輸入和輸出。讓運算放大器正常運行所必需的其它一些管腳，諸如電源管腳、接零管腳等并未畫出。,P1U2A The Operational Amplifier,在實際電路中使用運算放大器時，后者是必要的，但在本文中討論理想的運算放大器的應用時則不必考慮后者。兩個輸入電壓和輸出電壓用符號U 、U 和Uo 表示。每一個電壓均指的是相對于接零管腳的電位。運算放大器是差分裝置。差分的意思是：相對于接零管腳的輸出電壓可由下式表示。,P1U2A The Operational Amplifier,Integrated circuit technology allows construction of output of the device acts like an ideal voltage source.,集成電路技術(shù)使得在非常小的一塊半導體材料的復合 “芯片”上可以安裝許多放大器電路。運算放大器成功的一個關(guān)鍵就是許多晶體管放大器“串聯(lián)”以產(chǎn)生非常大的整體增益。也就是說，等式(1-2A-1)中的數(shù)A約為100,000或更多 (例如，五個晶體管放大器串聯(lián)，每一個的增益為10，那么將會得到此數(shù)值的A )。,P1U2A The Operational Amplifier,第二個重要因素是這些電路是按照流入每一個輸入的電流都很小這樣的原則來設(shè)計制作的。第三個重要的設(shè)計特點就是運算放大器的輸出阻抗(Ro )非常小。也就是說運算放大器的輸出是一個理想的電壓源。,P1U2A The Operational Amplifier,This shows that if A is very large, , by using an Op-Amp we trade off “power” for “control”.,這表明，如果A 非常大，那么電路的增益與A 的精確值無關(guān)并能夠通過R1和R2的選擇來控制。這是運算放大器設(shè)計的重要特征之一 在信號作用下，電路的動作僅取決于能夠容易被設(shè)計者改變的外部元件，而不取決于運算放大器本身的細節(jié)特性。,P1U2A The Operational Amplifier,注意，如果A=100,000， 而(R1 +R2) /R1=10，那么為此優(yōu)點而付出的代價是用一個具有100,000倍電壓增益的器件產(chǎn)生一個具有10倍增益的放大器。從某種意義上說，使用運算放大器是以 “能量”為代價來換取“控制” 。,P1U2A The Operational Amplifier,A similar mathematical analysis can be made on any Op-Amp circuit, but this is cumbersome and there are some very useful shortcuts that involve application of the two laws of Op-Amps which we now present.,對各種運算放大器電路都可作類似的數(shù)學分析，但是這比較麻煩，并且存在一些非常有用的捷徑，其涉及目前我們提出的運算放大器兩個定律應用。,P1U2A The Operational Amplifier,The first law states that The second law states that ,1) 第一個定律指出：在一般運算放大器電路中，可以假設(shè)輸入端間的電壓差為零，也就是說， 2) 第二個定律指出：在一般運算放大器電路中，兩個輸入電流可被假定為零：,P1U2A The Operational Amplifier,The first law is due to the into either of the two inputs.,第一個定律是因為內(nèi)在增益A的值很大。例如，如果運算放大器的輸出是1V ，并且A=100,000, 那么 ( )=10-5V 這是一個非常小、可以忽略的數(shù)，因此可設(shè)U+=U-。第二個定律來自于運算放大器的內(nèi)部電路結(jié)構(gòu)，此結(jié)構(gòu)使得基本上沒有電流流入任何一個輸入端。,P1U2A The Operational Amplifier,