外文文獻翻譯--數(shù)字電壓表技術(shù)

1、<p><b>　　中文2735字</b></p><p><b>　　物理與電子學(xué)院</b></p><p>　　2013屆畢業(yè)設(shè)計外文文獻翻譯</p><p>　　文獻名稱： The DVM technology </p><p&g

2、t;　　數(shù)字電壓表技術(shù) </p><p>　　學(xué)生姓名： </p><p>　　專 業(yè)： 電子科學(xué)與技術(shù) </p><p>　　指導(dǎo)教師： </p>

3、<p>　　完成時間： 2013年5月 </p><p>　　The DVM technology</p><p>　　Front side</p><p>　　Copyright of this circuit belongs to smart kit electronics. In this page we

4、will use this circuit to discuss for improvements and we will introduce some changes based on original schematic</p><p>　　General Description </p><p>　　This is an easy to build, but nevertheless

5、 very accurate and useful digital voltmeter. It has been designed as a panel meter and can be used in DC power supplies or anywhere else it is necessary to have an accurate indication of the voltage present. The circuit

6、employs the ADC (Analogue to Digital Converter) I.C. CL7107 made by INTERSIL. This IC incorporates in a 40 pin case all the circuitry necessary to convert an analogue signal to digital and can drive a series of four seve

7、n segment LED disp</p><p>　　Technical Specifications - Characteristics</p><p>　　Supply Voltage: ............. +/- 5 V (Symmetrical)</p><p>　　Power requirements: ..... 200 mA (maximu

8、m)</p><p>　　Measuring range: .......... +/- 0-1,999 VDC in four ranges</p><p>　　Accuracy: ....................... 0.1 %</p><p><b>　　FEATURES</b></p><p>　　Sm

9、all size </p><p>　　Easy construction </p><p><b>　　Low cost.</b></p><p>　　Simple adjustment.</p><p>　　Easy to read from a distance.</p><p>　　Few

10、 external components.</p><p>　　How it Works </p><p>　　In order to understand the principle of operation of the circuit it is necessary to explain how the ADC IC works. This IC has the following

11、very important features:</p><p>　　Great accuracy.</p><p>　　It is not affected by noise.</p><p>　　No need for a sample and hold circuit.</p><p>　　It has a built-in clock

12、.</p><p>　　It has no need for high accuracy external components.</p><p>　　Schematic (fixed 16-11-09)</p><p>　　7-segment display pinout MAN6960</p><p>　　An Analogue to D

13、igital Converter, (ADC from now on) is better known as a dual slope converter or integrating converter. This type of converter is generally preferred over other types as it offers accuracy, simplicity in design and a rel

14、ative indifference to noise which makes it very reliable. The operation of the circuit is better understood if it is described in two stages. During the first stage and for a given period the input voltage is integrated,

15、 and in the output of the integrator at the </p><p>　　All this sounds quite easy but it is in fact a series of very complex operations which are all made by the ADC IC with the help of a few external compone

16、nts which are used to configure the circuit for the job. In detail the circuit works as follows. The voltage to be measured is applied across points 1 and 2 of the circuit and through the circuit R3, R4 and C4 is finally

17、 applied to pins 30 and 31 of the IC. These are the input of the IC as you can see from its diagram. (IN HIGH & IN LOW respecti</p><p>　　Construction </p><p>　　First of all let us consider a

18、 few basics in building electronic circuits on a printed circuit board. The board is made of a thin insulating material clad with a thin layer of conductive copper that is shaped in such a way as to form the necessary co

19、nductors between the various components of the circuit. The use of a properly designed printed circuit board is very desirable as it speeds construction up considerably and reduces the possibility of making errors. 

20、 To protect the board during storag</p><p>　　Soldering the components to the board is the only way to build your circuit and from the way you do it depends greatly your success or failure. This work is not v

21、ery difficult and if you stick to a few rules you should have no problems. The soldering iron that you use must be light and its power should not exceed the 25 Watts. The tip should be fine and must be kept clean at all

22、times. For this purpose come very handy specially made sponges that are kept wet and from time to time you can wipe th</p><p>　　DO NOT use soldering flux apart from that which is already included in your sol

23、der. Too much flux can cause many problems and is one of the main causes of circuit malfunction. If nevertheless you have to use extra flux, as it is the case when you have to tin copper wires, clean it very thoroughly a

24、fter you finish your work.</p><p>　　In order to solder a component correctly you should do the following:</p><p>　　Clean the component leads with a small piece of emery paper.</p><p&g

25、t;　　Bend them at the correct distance from the component’s body and insert the component in its place on the board.</p><p>　　You may find sometimes a component with heavier gauge leads than usual, that are t

26、oo thick to enter in the holes of the p.c. board. In this case use a mini drill to enlarge the holes slightly. Do not make the holes too large as this is going to make soldering difficult afterwards.</p><p>

27、　　Take the hot iron and place its tip on the component lead while holding the end of the solder wire at the point where the lead emerges from the board. The iron tip must touch the lead slightly above the p.c. board.<

28、/p><p>　　When the solder starts to melt and flow wait till it covers evenly the area around the hole and the flux boils and gets out from underneath the solder. The whole operation should not take more than 5 s

29、econds. Remove the iron and allow the solder to cool naturally without blowing on it or moving the component. If everything was done properly the surface of the joint must have a bright metallic finish and its edges shou

30、ld be smoothly ended on the component lead and the board track. If the solder l</p><p>　　Take care not to overheat the tracks as it is very easy to lift them from the board and break them.</p><p&g

31、t;　　When you are soldering a sensitive component it is good practice to hold the lead from the component side of the board with a pair of long-nose pliers to divert any heat that could possibly damage the component.</

32、p><p>　　Make sure that you do not use more solder than it is necessary as you are running the risk of short-circuiting adjacent tracks on the board, especially if they are very close together.</p><p&

33、gt;　　When you finish your work, cut off the excess of the component leads and clean the board thoroughly with a suitable solvent to remove all flux residues that may still remain on it.</p><p>　　0 - 2 V ....

34、........ R3 = 0 ohm 1%</p><p>　　0 - 20 V ........... R3 = 1.2 Kohm 1%</p><p>　　0 - 200 V .......... R3 = 12 Kohm 1%</p><p>　　0 - 2000 V ......... R3 = 120 Kohm 1%</p><p&g

35、t;　　When you have finished all the soldering on the board and you are sure that everything is OK you can insert the IC in its place. The IC is CMOS and is very sensitive to static electricity. It comes wrapped in alumini

36、um foil to protect it from static discharges and it should be handled with great care to avoid damaging it. Try to avoid touching its pins with your hands and keep the circuit and your body at ground potential when you i

37、nsert it in its place.</p><p>　　Connect the circuit to a suitable power supply ρ 5 VDC and turn the supply on. The displays should light immediately and should form a number. Short circuit the input (0 V) an

38、d adjust the trimmer P1 until the display indicates exactly «0».</p><p>　　If it does not work </p><p>　　Check your work for possible dry joints, bridges across adjacent tracks or solde

39、ring flux residues that usually cause problems. </p><p>　　Check again all the external connections to and from the circuit to see if there is a mistake there.</p><p>　　See that there are no comp

40、onents missing or inserted in the wrong places. </p><p>　　Make sure that all the polarised components have been soldered the right way round.</p><p>　　Make sure the supply has the correct voltag

41、e and is connected the right way round to your circuit. - Check your project for faulty or damaged components.</p><p><b>　　數(shù)字電壓表技術(shù)</b></p><p><b>　　引言</b></p><p

42、>　　這是一個很容易建立并且非常準確和有用的數(shù)字電壓表。它被設(shè)計成一個面板儀表，可用于直流電源供應(yīng)器或其他需要有一個準確電壓指示的地方。該電路采用的ADC（模擬數(shù)字轉(zhuǎn)換器）集成電路CL7107由Intersil公司生產(chǎn)。該IC采用40引腳的情況下整合了所有必要的電路模擬信號轉(zhuǎn)換為數(shù)字，可以直接驅(qū)動4個7段LED顯示。在IC中內(nèi)置的電路是數(shù)字轉(zhuǎn)換器，比較器，一個時鐘，一個解碼器和一個7段LED顯示驅(qū)動器模擬。在這里它描述了一個可以顯

43、示在0-1999電壓范圍的直流電壓電路。</p><p>　　LED顯示屏數(shù)字電壓表技術(shù)規(guī)格 - 特征</p><p>　　電源電壓：.............+ / - 5V（對稱）。</p><p>　　電源要求：.............200mA（最大）。</p><p>　　測量范圍：.............+ / - 0-1,9

44、99V在四個范圍。</p><p>　　精度：.................0.1％。</p><p><b>　　特征：</b></p><p><b>　　小尺寸。</b></p><p><b>　　簡易建筑。</b></p><p><

45、b>　　成本低。</b></p><p><b>　　簡單的調(diào)整。</b></p><p><b>　　易于讀取距離。</b></p><p><b>　　很少的外部元件。</b></p><p>　　數(shù)字電壓表的基本原則</p><p&g

46、t;　　為了了解電路的運作的原則，說明ADC的集成電路工程是必要的。該集成電路具有以下非常重要的特點：</p><p><b>　　準確性。</b></p><p><b>　　抗干擾性。</b></p><p>　　無需要一個采樣保持電路。</p><p>　　它有一個內(nèi)置的時鐘。</p&g

47、t;<p>　　它不需要精度高的外部元件。</p><p>　　一個模擬數(shù)字轉(zhuǎn)換器(ADC)，從現(xiàn)在起更好的稱為雙斜率轉(zhuǎn)換器或集成轉(zhuǎn)換器。這種類型的轉(zhuǎn)換器通常優(yōu)于其他類型，因為它提供了準確，簡潔的設(shè)計和它可以將相對不重要的噪音變得非?？煽?。如果將電路分兩個階段描述，該電路的操作將更好的理解。在第一階段的輸入集成電壓和最后階段的輸出集成電壓中有一個電壓與輸入電壓成正比。在預(yù)設(shè)的時間結(jié)束時，積分將到達內(nèi)

48、部基準電壓以及輸出電路會逐漸降低直至達到零參考電壓水平。第二個階段就是所謂的負斜率時期，其持續(xù)時間由第一階段積分器輸出而定。作為第一個操作時間是固定的，第二個變量的長度就可以比較兩個這樣的輸入電壓，其實是相對于內(nèi)部參考電壓，其結(jié)果是編碼，然后發(fā)送到顯示。</p><p>　　示意圖（固定16-11-09）</p><p>　　7段顯示器引出線MAN6960</p><p

49、>　　這一切聽起來很容易，但實際上它是一系列非常復(fù)雜的操作，這些都是由ADC集成電路作出了很少的外部元件，幫助它們用來配置工作的電路。詳細的電路的工作原理如下。為了進行測量，需要將電壓施加于電路的1和2點，最后通過電路的R3，R4和C4應(yīng)用到集成電路的引腳30和31。從下圖你可知這是該集成電路的輸入(分別為高與低)。R1電阻的C1一起用來設(shè)置內(nèi)部振蕩器(時鐘)，該設(shè)置約48Hz。在這個時鐘速率大約有三個不同的每秒讀數(shù)。連接集成電路

50、引腳33和34之間的電容已被選定，以彌補由內(nèi)部參考電壓帶來的誤差，并保持穩(wěn)定的顯示。電容C3和電阻R5在一起的電路是輸入電壓的集成電路，同時它可避免任何使電路更快的分裂輸入電壓，從而使錯誤的可能性大大減少進而使電路更穩(wěn)定。在沒有輸入電壓時電容器C5強迫儀器顯示為零。當(dāng)輸入為零時電阻R2和P1一起用來調(diào)整儀器在設(shè)置過程中顯示為零。電阻R6的控制電流允許流經(jīng)顯示，以便使電路在沒有損壞的前提下顯示充分的亮度。至于我們上面已經(jīng)提到的芯片它能夠驅(qū)

51、動4個共陽極LED顯示屏。這三個最右邊的顯示器相連，使他們可以顯示所有從0到9的數(shù)字，而從左邊第一個只能顯示數(shù)字1，當(dāng)電壓為負“-”</p><p>　　數(shù)字電壓表印刷電路板的加工</p><p>　　首先讓我們考慮建立一個印刷電路板上的電子電路的基礎(chǔ)知識。該印刷電路板是由薄絕緣銅的導(dǎo)電復(fù)合材料薄層形成，這樣以形成電路之間的各組成部分的必要的導(dǎo)體。一個設(shè)計完善的印刷電路板是非?？扇〉?，因為

52、它大大加快了加工，并大大減少了決策失誤的可能性。為了保護印刷電路板在存儲過程中被氧化和保證它到達你所要求的完美的條件，在生產(chǎn)過程中將銅鍍錫的同時起表面還要覆蓋一層特殊的漆，這樣不僅防止了它被氧化，也使焊接更容易。</p><p>　　焊接的部件，印刷電路板是建立你的電路的唯一的方式和你在做板時很大程度上取決了你的成功或失敗。這項工作也并不是很困難，如果你堅持有一些規(guī)則你應(yīng)該沒有問題。在你使用電烙鐵時，其功率不應(yīng)超

53、過25瓦。它的尖應(yīng)該是好的，并且必須時刻保持清潔。為此我們特地準備了一特制海綿并使其保持潮濕，這樣可以不時擦拭熱烙鐵尖，從而去除積累在它上面的殘渣。</p><p>　　如果烙鐵尖不能清洗或更換，請勿用文件或砂紙弄臟或磨損其尖部。在市場上有許多不同類型的焊接劑，你應(yīng)該選擇一個優(yōu)質(zhì)的一個在其核心包含必需的流量的焊接劑，以保證每次焊接時都能完美的接合。</p><p>　　不使用助焊劑除了在你

54、的焊接劑里已含有助焊劑。太多的流量可能會導(dǎo)致許多問題，也是電路故障的主要原因之一。但如果您必須使用額外的流量，因為它是在你不得不將銅線鍍錫的情況下，將起徹底清除干凈后你完成了你的工作。</p><p>　　為了焊接組件正確，您應(yīng)該執(zhí)行下列操作：</p><p>　　用一小塊砂紙清潔清潔組件。</p><p>　　彎曲組件使它們之間有一合適的距離并插入在印刷電路板中的

55、正確地位組成部分。</p><p>　　你有時可能會發(fā)現(xiàn)比起平常還會有重計部分，它將過于厚而不能進入個人電腦印刷電路板的孔。在這種情況下使用的小型鉆孔略有放大。不要使孔太大，因為這將會使焊接困難。</p><p>　　拿著熱鐵將其尖端放在組件的一角上，同時將焊錫絲末梢放在尖端的一個點上。烙鐵頭必須觸及略高于印刷電路板的地方。</p><p>　　當(dāng)焊錫絲開始融化和流

56、動等待它均勻覆蓋孔周圍的區(qū)域和通量癤并且焊料從下面流出。整個過程不應(yīng)超過5秒。清除烙鐵，讓焊接劑自然冷卻不吹，或移動組件。如果一切處理得當(dāng)則表面聯(lián)合處有一個光明的金屬質(zhì)感，其邊緣應(yīng)該是平滑的并且有一軌道面。如果焊料看起來暗淡無光，有裂痕的，或有一個氣泡的形狀，那么你虛焊了和你應(yīng)該清除焊接劑(用泵，或焊芯)然后重做它。</p><p>　　注意不要過熱的軌道，因為它是很容易從其電路板上解除從而損壞電路板。</

57、p><p>　　在你焊接一個敏感元件時，很好的做法是用一個長鼻子鉗子夾著電路板組件的邊緣進行熱轉(zhuǎn)移但是那樣容易損壞組件。</p><p>　　確保你不使用過多的焊料是必需的，因為你正在冒著毗鄰軌道短路的風(fēng)險，特別是如果他們都非常接近時。</p><p>　　當(dāng)你完成你的工作時，切斷組件的多余部分和用適當(dāng)?shù)娜軇﹣韽氐浊宄赡苓€留在電路板上的助焊劑殘留物。</p>

58、;<p>　　更換的電阻按照下表：</p><p>　　0 - 2V............ R3 = 0歐姆1％</p><p>　　0 - 20V........... R3 = 1.2千歐1％</p><p>　　0 - 200V.......... R3 = 12千歐1％</p><p>　　0 - 2000V.....

59、.... R3 = 120千歐1％</p><p>　　當(dāng)您完成所有的電路板上焊接和您確信一切正常，可以插入在其位芯片。該IC是CMOS類型于是對靜電非常敏感。它有鋁箔包裹以防止靜電放電，并應(yīng)小心處理，以免損壞它。盡量避免用你的手接觸引腳，并且保持地面電路和你的身體電位在你插入的位置。電路連接到一個合適的電源ρ5伏直流電上，開啟電源。在光顯示區(qū)應(yīng)立即形成一個數(shù)字。短路輸入（0V）</p><p

60、>　　和調(diào)整微調(diào)小屏幕顯示，直到完全去掉0。</p><p><b>　　故障檢查簡介</b></p><p>　　檢查您可能造成的虛焊，跨越鄰近軌道或助焊劑殘留物的橋梁工作，通常會造成問題。再次檢查所有的電路和外部連接，看看是否有一個錯誤。</p><p>　　看是否有任何組件丟失或錯誤的地方插入：</p><p&g