簡易模擬集成萬用表

20132014

學(xué)年

第2

學(xué)期《

模擬電子技術(shù)課程計(jì)報(bào)告題專

目業(yè)

簡模集萬表電工及自化班

級12電工及自化1）班word檔可自由復(fù)制編輯

課題名指導(dǎo)教（職稱）

任務(wù)書簡易模集成萬用表江春紅執(zhí)行時(shí)

2013~2014學(xué)年

第

學(xué)期

第14

周學(xué)生姓張羽晨徐晶晶何永康

學(xué)號120914107112091410601209141018

承擔(dān)任設(shè)計(jì)直電壓表并進(jìn)仿真設(shè)計(jì)直電流表并進(jìn)仿真設(shè)計(jì)交電壓表并進(jìn)仿真丁

偉

1209141008

設(shè)計(jì)交電流表并進(jìn)仿真孫學(xué)峰鄧忠建

12091410421209141007

設(shè)計(jì)歐表并進(jìn)行仿整理測數(shù)據(jù)、整理完成課設(shè)計(jì)報(bào)告設(shè)計(jì)目

1、通過對集成萬表的的計(jì)了解由成運(yùn)組成的電壓、電等電路，學(xué)在實(shí)際路中應(yīng)用；2、一步熟集成運(yùn)放的性應(yīng)用1、流電壓量范圍0~25V）±5%；2、流電流量范圍0~20mA）±5%3交流電測量范圍及率范圍有效值0~10V）±5%，50Hz~1000Hz設(shè)計(jì)要4、流電流量范圍及頻范圍：效值（0~20mA）±5%；5、姆表測（Ω；6、用模擬成電路，器自選。word檔可自由復(fù)制編輯

緒論萬用電表簡稱萬用表或三用表在國家標(biāo)準(zhǔn)中稱作復(fù)用表萬用電表實(shí)際上是一種可以進(jìn)行多種項(xiàng)目測量的便攜式儀器主要用于測量電壓電流、電阻另外可粗略判斷電容器、晶體三極管及二極管、集成電路等元器件的性能好壞。在測量中萬用電表的接入因不影響被測電路原來的工作狀態(tài)這就要求電壓表應(yīng)具有無窮大的輸入電阻電流表的內(nèi)阻應(yīng)為零但實(shí)際上萬用電表表頭的可動(dòng)線圈總有一定的電阻，例如100uA的表，其內(nèi)阻約為1K，用它進(jìn)行測量時(shí)將會(huì)影響被測量，會(huì)引起誤差此外交流電表中整流二極管的壓降和非線性特性也會(huì)產(chǎn)生誤差如果在萬用電表中使用運(yùn)算放大器就能大大降低這些誤差提高測量精度在歐姆表中采用運(yùn)算放大器，不僅能得到線性刻度，還能實(shí)現(xiàn)自動(dòng)調(diào)零。運(yùn)算放大器電路性能的優(yōu)劣直接影響到萬用表的性能。本文從運(yùn)算放大器電路的結(jié)構(gòu)、原理出發(fā)，在闡述運(yùn)算放大器電路結(jié)構(gòu)、原理的基礎(chǔ)上用運(yùn)算放大器設(shè)計(jì)電路實(shí)現(xiàn)萬用表的電路設(shè)計(jì)。通過仿真與實(shí)際電路性能指標(biāo)的測試、分析、比較,總結(jié)出各種電路方案的特點(diǎn),為電路設(shè)計(jì)初學(xué)者提供一定的參考借鑒。word檔可自由復(fù)制編輯

目錄任務(wù)書·························································································································緒論····························································································································3第一章題目要求與方案論證··························································································51.1簡模擬集成萬用表···························································································1.1.1目要求···································································································1.1.2方論證·································································································1.2課設(shè)計(jì)目的·····································································································第二章電子線路設(shè)計(jì)····································································································62.1萬表工作原理·································································································62.1.1直流電壓原理··························································································2.1.2直流電流原理··························································································2.1.3交流電壓原理··························································································2.1.4交流電流原理··························································································2.1.5電阻原理································································································92.2運(yùn)制萬用表的電路設(shè)·················································································102.2.1圖：·····································································································102.2.2流電壓的電路圖：···················································································122.2.3流電流的電路圖：···················································································122.2.4流電壓的電路圖：···················································································132.2.5流電流的電路圖：···················································································132.2.6姆表電路圖：·························································································14第三章結(jié)果與分析······································································································153.1用用測量各種電流、電壓和電·····································································153.1.1直電流的測量······················································································153.1.2交電流的測量·······················································································153.1.3流電壓的測量·························································································163.1.4交電壓的測量·······················································································173.2測結(jié)及分析·································································································173.2.1流電壓的測量結(jié)果及分析：·······································································173.2.2流電流的測量結(jié)果及分析：·······································································173.2.3流電壓的測量結(jié)果及分析：·······································································183.2.4流電流的測量結(jié)果及分析：·······································································183.2.5姆表測量結(jié)果及分析：·············································································18總結(jié)···························································································································19參考文獻(xiàn)·····················································································································19附錄···························································································································19word檔可自由復(fù)制編輯

第一章

題目要求與案論證1.1易模擬成萬用表1.1.1題目要求1、直流電壓測量范圍0~25V）±5%；2、直流電流測量范圍）±5%；3、交流電壓測量范圍及頻率范圍：有效值（）±5%，50Hz~1000Hz4、交流電流測量范圍及頻率范圍：有效值（）±5%；5、歐姆表測程0~1KΩ5%；6、采用模擬集成電路，器件自選。1.1.2方案論證在測量中電表的接入應(yīng)不影響被測電路的原工作狀態(tài)這就要求電壓表應(yīng)具有無窮大的輸入電阻流表的內(nèi)阻應(yīng)為零實(shí)際上用表表頭的可動(dòng)線圈總有一定的電阻。例如100μA的表頭，其內(nèi)阻約為1KΩ，用它進(jìn)行測量時(shí)將影響被測量量，引起誤差。此外交流電表中的整流二極管和非線性特性也會(huì)產(chǎn)生誤差如果在萬用表中使用運(yùn)算放器，就能大大降低這些誤差高測量精度在歐姆表中采用運(yùn)算放大器不僅能得到線性刻度，還能實(shí)現(xiàn)自動(dòng)調(diào)零。1.2程設(shè)計(jì)的1、通過對集成萬用表的的設(shè)計(jì)、了解由集成運(yùn)放組成的測電壓、電流等電路，學(xué)會(huì)在實(shí)際電路中應(yīng)用；2、進(jìn)一步熟悉集成運(yùn)放的線性應(yīng)用。word檔可自由復(fù)制編輯

第二章

電子線路設(shè)2.1用表工原理萬用表的基本原理是利用一只靈敏的磁電式直流電流（微安表做表頭當(dāng)微小電流通過表頭，就會(huì)有電流指示表頭不能通過大電流，所以，必須在表頭上并聯(lián)與串聯(lián)一些電阻進(jìn)行分流或降壓，從而測出電路中的電流、電壓和電阻。下面分別介紹。2.1.1測直流電壓原理圖2-1為同相端輸入高進(jìn)度直流電壓表電原理圖為了減小表頭參數(shù)對測量精度的影響，將表頭至于運(yùn)算放大器的反饋回路中，這時(shí)，流經(jīng)表頭的電流與表頭的參數(shù)無關(guān)，只要改變R1一個(gè)電阻，就可以進(jìn)行量程的切換。圖表頭電流I與被測電壓Ui的關(guān)系為：I=Ui/R1應(yīng)當(dāng)指出圖1適用于測量電路與運(yùn)算放大器共地的有關(guān)電路此外當(dāng)被測電壓較高時(shí)，在運(yùn)放的輸入端應(yīng)設(shè)置衰減器。word檔可自由復(fù)制編輯

2.1.2測直流電流原理圖2-2是浮地直流電流表的電原理圖電流測量中地電流的測量是普遍存在的。例如若被測電流無接地點(diǎn)屬于這種情況為此應(yīng)把運(yùn)算放大器的電源也對地浮動(dòng)。按此種方式構(gòu)成的電流表就可像常規(guī)電流表那樣，串聯(lián)在任何電流通路中測量電流。圖表頭電流I與被測電流I1間關(guān)系為：I=(1+R1/R3)I

1可見改變電阻比可調(diào)節(jié)流過電流表的電流以提高靈敏度該圖被測電流回路無接地點(diǎn)，即所謂浮地電流時(shí)，則把運(yùn)算放大器的電源也對地浮起來。word檔可自由復(fù)制編輯

2.1.3測交流電壓原理由運(yùn)算放大器二極管整流橋和直流毫安表組成的交流電壓表如圖2-3所示被測交流電壓Ui加到運(yùn)算放大器的同相端，故有很高的輸入阻抗，又因?yàn)樨?fù)反饋能減小反饋回路中的非線性影響故把二極管橋路和表頭至于運(yùn)算放大器的反饋回路中減小二極管本身非線性的影響。圖表頭電流I與被測電壓ui的關(guān)系為：I=Ui/R1word檔可自由復(fù)制編輯

RR2.1.4測交流電流原理圖4圖2-4為浮地交流電流表頭讀數(shù)由被測交流電流的全波整流平均值決定，即RI)I22.1.5測電阻原理圖2-5在此電路中，運(yùn)算放大器改用單電源供電，北側(cè)電阻跨在運(yùn)算放大器的反饋回路中，同相端加基準(zhǔn)電壓U。REFword檔可自由復(fù)制編輯

可見，電流I于被測電阻成正比，而且表頭具有線性刻度，改變值，可改變歐姆表的量程。這種歐姆表能自動(dòng)調(diào)零Rx=0是電路改成電壓跟隨器U＝U,故表頭電OREF流為零，從而實(shí)現(xiàn)了自動(dòng)調(diào)零。二極管D起保護(hù)作用，如果沒有D，當(dāng)Rx超量程時(shí)，特別是當(dāng)→∞，運(yùn)算放大器的輸出電壓將接近電源電壓使表頭過載有了D就可使輸出鉗位，防止表頭過載。調(diào)整R2，可實(shí)現(xiàn)滿量程調(diào)節(jié)。2.2運(yùn)放制萬用表的電設(shè)計(jì)2.2.1總圖：如圖，為設(shè)計(jì)的總電路圖。word檔可自由復(fù)制編輯

電路說明黑框以外部位是萬用表的內(nèi)部結(jié)構(gòu)黑框以內(nèi)是四種可能的待測元件四種功能的切換是以開關(guān)、S3、的控制完成的，其中在圖示初始狀態(tài)下，開關(guān)S1賦予控制鍵A，其余三個(gè)的控制鍵是B，這就能有四種組合方式，從而達(dá)到四種電表的測量功能。A1010

B0110

電表類型直流電流交流電壓直流電壓交流電流其中1示對應(yīng)鍵在初始態(tài)下按下，0表示初態(tài)。黑框中以類似的方式快速切換，便于仿真的進(jìn)行。word檔可自由復(fù)制編輯

2.2.2直流電壓的電路圖：說明：5v為測直流電壓2.2.3直流電流的電路圖：說明：為待測直流電流word檔可自由復(fù)制編輯

2.2.4交流電壓的電路圖：說明：5V為測流電壓有效值2.2.5交流電流的電路圖：說明：為待測交流電流峰值word檔可自由復(fù)制編輯

2.2.6歐姆表電路圖：說明：R6為測電阻，可制程word檔可自由復(fù)制編輯

第三章3.1用萬用測量各種電、電壓電阻對所設(shè)計(jì)的各個(gè)電表進(jìn)行仿真。3.1.1直流電流的測量

結(jié)果與分析3.1.2交流電流的測量word檔可自由復(fù)制編輯

3.1.3直流電壓的測量word檔可自由復(fù)制編輯

3.1.4交流電壓的測量3.2測量結(jié)及分析3.2.1直流電壓的測量結(jié)果及分析：測量電壓

絕對誤差

相對誤差輸入電壓

10.003V15.003V20.004V

0.040%0.030%0.020%0.020%3.2.2直流電流的測量結(jié)果及分析：測量電流

絕對誤差

相對誤差5mA

0.0600%輸入電流

10mA15mA

0.0200%0.0067%word檔可自由復(fù)制編輯

3.2.3交流電壓的測量結(jié)果及分析：輸入電壓

tcos100cos100cos100

測量電壓1.0400V4.0100V9.0200V

絕對誤差0.0400V0.0100V0.0200V

相對誤差4.00%2.50%2.20%3.2.4交流電流的測量結(jié)果及分析：

測量電流5.002mA

絕對誤差0.002mA

相對誤差0.040%輸入電流

0.003mA

0.030%

0.003mA

0.020%3.2.5歐姆表測量結(jié)果及分析：輸入電阻

ΩΩΩ

測量電阻303.5Ω601.8Ω902.2Ω

絕對誤差3.5Ω1.8Ω2.2Ω

相對誤差0.44%0.31%0.22%word檔可自由復(fù)制編輯

總結(jié)萬用表主要用于測量電壓電流電阻另外可粗略判斷電容器晶體三極管及二極管、集成電路等元器件的性能好壞文從運(yùn)算放大器電路的結(jié)構(gòu)、原理出發(fā)，在闡述運(yùn)算放大器電路結(jié)構(gòu)、原理的基礎(chǔ)用運(yùn)算放大器設(shè)計(jì)電路實(shí)現(xiàn)萬用表的電路設(shè)計(jì)。通過仿真與實(shí)際電路性能指標(biāo)的測試、分析、比較,結(jié)出各種電路方案的特點(diǎn),為電路設(shè)計(jì)初學(xué)者提供一定的參考借鑒課題中萬用電表的電性能測試要用標(biāo)準(zhǔn)電壓電流表校正歐姆表用標(biāo)準(zhǔn)電阻校正?？紤]實(shí)驗(yàn)要求不高，建議用數(shù)字式萬用電表作為標(biāo)準(zhǔn)表。通過這次課程設(shè)計(jì)讓我們懂得了理論與實(shí)際操作之間的差距我們體會(huì)到了模電理論知識的實(shí)用發(fā)現(xiàn)了自身知識的不足，積累了課程設(shè)計(jì)的經(jīng)驗(yàn)。小組合作共同完成任務(wù)更讓我們學(xué)會(huì)了合理分工與協(xié)調(diào)合作會(huì)到合作的重要性認(rèn)識到每一個(gè)課題務(wù)都需要小組成員的共同努力與付出課程設(shè)計(jì)從各方面讓我們組全體成員都學(xué)到了很多，十分感謝學(xué)校給我們學(xué)習(xí)的機(jī)會(huì)。由于我們第一次進(jìn)行此類課程設(shè)計(jì)在完成課題時(shí)難免有很多紕漏所以在課程設(shè)計(jì)過程中江老師的多次認(rèn)真輔導(dǎo)和熱心幫助讓我們有很大進(jìn)步使我們受益匪淺最后我們?nèi)M成員對江老師的辛勤輔導(dǎo)表示由衷的感謝。參考文獻(xiàn)[1]清華大學(xué)電子學(xué)教研組編童詩白華成英主編.《模擬電子技術(shù)基礎(chǔ)第版北京；高等教育出版社，[2]王艷春主編子技術(shù)實(shí)驗(yàn)與Multisim真》合肥；合肥工業(yè)大學(xué)出版社，[3]衣承斌，劉京南編《模擬集成電子技術(shù)基礎(chǔ)》南京；東南大學(xué)出版社，附錄一、實(shí)驗(yàn)設(shè)備和主要元器件1、運(yùn)算放器HA177412、毫伏表表頭滿偏電