外文翻译LED显示屏数字电压表(适用于毕业论文外文翻译+中英文

1、w 外文文献原稿和译文 原 稿front side copyright of this circuit belongs to smart kit electronics. in this page wewill use this circuit to discuss for improvements and we will introduce somechanges based on original schematicgeneral description this is an easy to build but nevertheless very accurate and useful d

2、igitalvoltmeter. it has been designed as a panel meter and can be used in dc powersupplies or anywhere else it is necessary to have an accurate indication of thevoltage present. the circuit employs the adc analogue to digital converteri.c. cl7107 made by intersil. this ic incorporates in a 40 pin ca

3、se all thecircuitry necessary to convert an analogue signal to digital and can drive aseries of four seven segment led displays directly. the circuits built into theic are an analogue to digital converter a comparator a clock a decoder and aseven segment led display driver. the circuit as it is desc

4、ribed here candisplay any dc voltage in the range of 0-1999 volts.technical specifications - characteristics supply voltage: . /- 5 v symmetrical power requirements: . 200 ma maximum measuring range: . /- 0-1999 vdc in four ranges accuracy: . 0.1 features small size easy construction low cost. simpl

5、e adjustment. easy to read from a distance.w few external components.how it works in order to understand the principle of operation of the circuit it isnecessary to explain how the adc ic works. this ic has the following veryimportant features: great accuracy. it is not affected by noise. no need fo

6、r a sample and hold circuit. it has a built-in clock. it has no need for high accuracy external components. schematic fixed 16-11-09w 7-segment display pinout man6960 an analogue to digital converter adc from now on is better known asa dual slope converter or integrating converter. this type of conv

7、erter isgenerally preferred over other types as it offers accuracy simplicity in designand a relative indifference to noise which makes it very reliable. the operationof the circuit is better understood if it is described in two stages. during thefirst stage and for a given period the input voltage

8、is integrated and in theoutput of the integrator at the end of this period there is a voltage which isdirectly proportional to the input voltage. at the end of the preset period theintegrator is fed with an internal reference voltage and the output of the circuitis gradually reduced until it reaches

9、 the level of the zero reference voltage. thissecond phase is known as the negative slope period and its duration depends onthe output of the integrator in the first period. as the duration of the firstoperation is fixed and the length of the second is variable it is possible tocompare the two and t

10、his way the input voltage is in fact compared to theinternal reference voltage and the result is coded and is send to the display. all this sounds quite easy but it is in fact a series of very complexoperations which are all made by the adc ic with the help of a few externalcomponents which are used

11、 to configure the circuit for the job. in detail thecircuit works as follows. the voltage to be measured is applied across points 1and 2 of the circuit and through the circuit r3 r4 and c4 is finally applied topins 30 and 31 of the ic. these are the input of the ic as you can see from itsdiagram. in

12、 high amp in low respectively. the resistor r1 together with c1ware used to set the frequency of the internal oscillator clock which is set atabout 48 hz. at this clock rate there are about three different readings persecond. the capacitor c2 which is connected between pins 33 and 34 of the ichas be

13、en selected to compensate for the error caused by the internal referencevoltage and also keeps the display steady. the capacitor c3 and the resistor r5are together the circuit that does the integration of the input voltage and at thesame time prevent any division of the input voltage making the circ

14、uit fasterand more reliable as the possibility of error is greatly reduced. the capacitor c5forces the instrument to display zero when there is no voltage at its input. theresistor r2 together with p1 are used to adjust the instrument during set-up sothat it displays zero when the input is zero. the

15、 resistor r6 controls the currentthat is allowed to flow through the displays so that there is sufficient brightnesswith out damaging them. the ic as we have already mentioned above is capableto drive four common anode led displays. the three rightmost displays areconnected so that they can display

16、all the numbers from 0 to 9 while the firstfrom the left can only display the number 1 and when the voltage is negative the- sign. the whole circuit operates from a symmetrical 5 vdc supply whichis applied at pins 1 5 v 21 0 v and 26 -5 v of the ic.construction first of all let us consider a few bas

17、ics in building electronic circuits on aprinted circuit board. the board is made of a thin insulating material clad witha thin layer of conductive copper that is shaped in such a way as to form thenecessary conductors between the various components of the circuit. the use ofa properly designed print

18、ed circuit board is very desirable as it speedsconstruction up considerably and reduces the possibility of making errors. toprotect the board during storage from oxidation and assure it gets to you inperfect condition the copper is tinned during manufacturing and covered with aspecial varnish that p

19、rotects it from getting oxidised and also makes solderingeasier. soldering the components to the board is the only way to build your circuitand from the way you do it depends greatly your success or failure. this work iswnot very difficult and if you stick to a few rules you should have no problems.

20、the soldering iron that you use must be light and its power should not exceedthe 25 watts. the tip should be fine and must be kept clean at all times. for thispurpose come very handy specially made sponges that are kept wet and fromtime to time you can wipe the hot tip on them to remove all the resi

21、dues thattend to accumulate on it.do not file or sandpaper a dirty or worn out tip. if the tip cannot be cleanedreplace it. there are many different types of solder in the market and youshould choose a good quality one that contains the necessary flux in its core toassure a perfect joint every time.

22、 do not use soldering flux apart from that which is already included inyour solder. too much flux can cause many problems and is one of the maincauses of circuit malfunction. if nevertheless you have to use extra flux as it isthe case when you have to tin copper wires clean it very thoroughly after

23、youfinish your work. in order to solder a component correctly you should do the following: clean the component leads with a small piece of emery paper. bend them at the correct distance from the components body and insertthe component in its place on the board. you may find sometimes a component wit

24、h heavier gauge leads than usualthat are too thick to enter in the holes of the p.c. board. in this case use a minidrill to enlarge the holes slightly. do not make the holes too large as this isgoing to make soldering difficult afterwards. take the hot iron and place its tip on the component lead wh

25、ile holding theend of the solder wire at the point where the lead emerges from the board. theiron tip must touch the lead slightly above the p.c. board. when the solder starts to melt and flow wait till it covers evenly the areaaround the hole and the flux boils and gets out from underneath the sold

26、er. thewhole operation should not take more than 5 seconds. remove the iron andallow the solder to cool naturally without blowing on it or moving thecomponent. if everything was done properly the surface of the joint must have awbright metallic finish and its edges should be smoothly ended on the co

27、mponentlead and the board track. if the solder looks dull cracked or has the shape of ablob then you have made a dry joint and you should remove the solder with apump or a solder wick and redo it. take care not to overheat the tracks as it is very easy to lift them from theboard and break them. when

28、 you are soldering a sensitive component it is good practice to holdthe lead from the component side of the board with a pair of long-nose pliers todivert any heat that could possibly damage the component. make sure that you do not use more solder than it is necessary as you arerunning the risk of s

29、hort-circuiting adjacent tracks on the board especially ifthey are very close together. when you finish your work cut off the excess of the component leads andclean the board thoroughly with a suitable solvent to remove all flux residuesthat may still remain on it. 0 - 2 v . r3 0 ohm 1 0 - 20 v . r3

30、 1.2 kohm 1 0 - 200 v . r3 12 kohm 1 0 - 2000 v . r3 120 kohm 1 when you have finished all the soldering on the board and you are surethat everything is ok you can insert the ic in its place. the ic is cmos and isvery sensitive to static electricity. it comes wrapped in aluminium foil toprotect it f

31、rom static discharges and it should be handled with great care toavoid damaging it. try to avoid touching its pins with your hands and keep thecircuit and your body at ground potential when you insert it in its place. connect the circuit to a suitable power supply 5 vdc and turn thesupply on. the di

32、splays should light immediately and should form a number.short circuit the input 0 v and adjust the trimmer p1 until the displayindicates exactly 0.if it does not work check your work for possible dry joints bridges across adjacent tracks orwsoldering flux residues that usually cause problems. check

33、 again all the external connections to and from the circuit to see ifthere is a mistake there. see that there are no components missing or inserted in the wrong places. make sure that all the polarised components have been soldered the rightway round. make sure the supply has the correct voltage and

34、 is connected the rightway round to your circuit. - check your project for faulty or damagedcomponents.sample power supply 1 sample power supply 2w 译 文引言 这是一个很容易建立并且非常准确和有用的数字电压表。它被设计成一个面板仪表，可用于直流电源供应器或其他需要有一个准确电压指示的地方。该电路采用的 adc（模拟数字转换器）集成电路 cl7107 由 intersil公司生产。该 ic 采用 40 引脚的情况下整合了所有必要的电路模拟信号转换为数

35、字，可以直接驱动 4 个 7 段 led 显示。在 ic 中内置的电路是数字转换器，比较器，一个时钟，一个解码器和一个 7 段 led 显示驱动器模拟。在这里它描述了一个可以显示在 0-1999 电压范围的直流电压电路。led 显示屏数字电压表技术规格 - 特征 电源电压：. / - 5v（对称）。 电源要求：.200ma（最大）。 测量范围：. / - 0-1999v 在四个范围。 精度：.0.1。 特征： 小尺寸。 简易建筑。 成本低。 简单的调整。 易于读取距离。 很少的外部元件。数字电压表的基本原则 为了了解电路的运作的原则，说明 adc 的集成电路工程是必要的。该集成电路具有以下非常

36、重要的特点：w 准确性。 抗干扰性。 无需要一个采样保持电路。 它有一个内置的时钟。 它不需要精度高的外部元件。 一个模拟数字转换器adc，从现在起更好的称为双斜率转换器或集成转换器。这种类型的转换器通常优于其他类型，因为它提供了准确，简洁的设计和它可以将相对不重要的噪音变得非常可靠。如果将电路分两个阶段描述，该电路的操作将更好的理解。在第一阶段的输入集成电压和最后阶段的输出集成电压中有一个电压与输入电压成正比。在预设的时间结束时，积分将到达内部基准电压以及输出电路会逐渐降低直至达到零参考电压水平。第二个阶段就是所谓的负斜率时期，其持续时间由第一阶段积分器输出而定。作为第一个操作时间是固定的，

37、第二个变量的长度就可以比较两个这样的输入电压，其实是相对于内部参考电压，其结果是编码，然后发送到显示。 示意图（固定 16-11-09）w 7 段显示器引出线 man6960 这一切听起来很容易，但实际上它是一系列非常复杂的操作，这些都是由 adc 集成电路作出了很少的外部元件，帮助它们用来配置工作的电路。详细的电路的工作原理如下。为了进行测量，需要将电压施加于电路的 1和 2 点，最后通过电路的 r3，r4 和 c4 应用到集成电路的引脚 30 和 31。从下图你可知这是该集成电路的输入分别为高与低。 电阻的 c1 一起用 r1来设置内部振荡器时钟，该设置约 48hz。在这个时钟速率大约有三

38、个不同的每秒读数。连接集成电路引脚 33 和 34 之间的电容已被选定，以弥补由内部参考电压带来的误差，并保持稳定的显示。电容 c3 和电阻 r5 在一起的电路是输入电压的集成电路，同时它可避免任何使电路更快的分裂输入电压，从而使错误的可能性大大减少进而使电路更稳定。在没有输入电压时电容器 c5 强迫仪器显示为零。当输入为零时电阻 r2 和 p1 一起用来调整仪器在设置过程中显示为零。电阻 r6 的控制电流允许流经显示，以便使电路在没有损坏的前提下显示充分的亮度。至于我们上面已经提到的芯片它能够驱动 4 个共阳极 led 显示屏。这三个最右边的显示器相连，使他们可以显示所有从 0 到 9 的数字，而从左边第一个只能显示数字 1，当电压为负“-”的时候。整个电路工作，从对称 5 伏直流电电源，这在引脚 15v申请，210v，26-5v集成电路。数字电压表印刷电路板的加工 首先让我们考虑建立一个印刷电路板上的电子电路的基础知识。该印刷电路板是由薄绝缘铜的导电复合材料薄层形成，这样以形成电路之间的w各组成部分的必要的导体。一个设计完善的印刷电路板是非常可取的，因为它大大加快了加工，并大大减少了决策失误的可能