電大《機電接口技術》期末考試重點復習題資料參考

1、電大機電接口技術期末考試重點復習題資料電大機電接口技術期末自測題輸入電壓過零，輸出電壓發(fā)生跳變。除此之外，輸出電壓保持不變。并希望輸入電壓大于零時輸出為高電平。則應選用（A 差動型電平檢測器比較器成穩(wěn)壓器。A 三端可調正電壓輸出C.固定型負電壓輸出一、選擇題1.要求電壓比較器僅在除此之外，輸出電壓保持不變。并希）。B同相輸入過零比較器C窗口D回差電壓比較器2.317為（）集B.固定型正電壓輸出D.三端可調負電壓輸出3.若希望電壓比較器在輸入小于+5V時輸出電壓為高電平，而在輸入大于十5V時輸出電壓為低電平。則應選用（）。A反相端輸入差動電平檢測器B過零比較器C窗口比較器D回差電壓比較器4.模擬

2、電壓比較器同運算放大器的主要區(qū)別是：模擬電壓比較器中的工作于（）。A.開環(huán)狀態(tài)B.負反饋狀態(tài)C.深度負反饋狀態(tài)D高電平狀態(tài)5.單向晶閘管有三個引腳：A、K和G，其中K為（）。A.陽極B.陰極C.控制極D門級6.AD202/AD204是基于（）原理的隔離放大器。A.變壓器耦合B.光電隔離C.繼電器隔離D,線性光電隔離7.運算放大器中的（）單元用于設置各級放大電路的靜態(tài)工作點。A.輸入級B.輸出級C.中間級D.偏置電路8.最早出現(xiàn)的電動機是（）。A.直流電動機B.交流電動機C.步進電動機D.直線電動機9.三相異步電動機改變同步轉速n0的方法是（）。A.調節(jié)轉子電阻B.調節(jié)定子電壓C.調節(jié)電源頻率D

3、.調節(jié)轉子電壓10.L290是一種（）-F4-|_L芯片。A.功率驅動芯片B.步進電機環(huán)形分配器C.細分電路D.轉速/電壓變換器二、簡答題1什么是光電耦合器件？光電耦合器件有什么特點？2隔離的實質是什么？有哪些常用的隔離？3SPWM的基本思想是什么？產生SPWM控制信號的方法主要有哪三種？4常用的隔離方式有哪幾種?光電隔離的特點是什么?5三相步進電機的工作方式哪幾種?其中“單”、“雙”、“拍”各是什么意思?6單向晶閘管的導通條件是什么？7什么是直流電動機？它有哪些優(yōu)點？8什么是步進電機？9環(huán)形分配器的主要功能是什么？三、分析計算題圖11.寫出圖1所示電路的傳遞函數(shù)。四、設計電路1、用7805設

4、計一個輸出電壓為+7V的穩(wěn)壓電路。機電接口技術期末自測題答案一、選擇題1、B2、A3、A4、A5、B6、A7、D8、A9、C10、D二、簡答題1什么是光電耦合器件？光電耦合器件有什么特點？光電耦合器件將發(fā)光元件和受光元件組合在一起，通過電-光-電這種轉換，利用“光”這一環(huán)節(jié)完成隔離功能，使輸入和輸出在電氣上是完全隔離的。根據(jù)受光元件的不同可分為晶體管輸出型和晶閘管輸出型兩類。光電耦合器具有三個特點：信號傳遞采取電-光-電的形式，能夠避免輸出端對輸入端可能產生的反饋和干擾，抑制噪聲干擾能力強；具有耐用、可靠性高和速度快等優(yōu)點。2隔離的實質是什么？有哪些常用的隔離？答：隔離的實質是把引進的干擾通道

5、切斷，從而達到隔離現(xiàn)場干擾的目的。測控裝置與現(xiàn)場信號之間、弱電和強電之間，常用的隔離方式有光電隔離、繼電器隔離、變壓器隔離、隔離放大器等。另外，在布線上也應該注意隔離。SPWM的基本思想是什么？產生SPWM控制信號的方法主要有哪三種？答：SPWM的基本思想是：保持輸出脈沖電壓幅度不變，用調節(jié)脈沖的寬度和間隔實現(xiàn)其平均值接近正弦（同時改變U和f）。將此脈沖電壓加到電機上，所得到的電流波形接近于正弦波。就硬件方面講，產生SPWM控制信號的方法主要有三種：1）采用微處理器。2）采用專用大規(guī)模集成電路。3）采用微處理器和專用大規(guī)模集成電路相結合。常用的隔離方式有哪幾種?光電隔離的特點是什么?答：常用的

6、隔離方式有光電隔離、繼電器隔離、變壓器隔離、隔離放大器等。光電隔離是以光為媒介傳輸信號的器件，輸入和輸出在電氣上是完全隔離的。具有較高的電氣隔離和抗干擾能力。三相步進電機的工作方式哪幾種?其中“單”、“雙”、“拍”各是什么意思?答：三相步進電機一般有單三拍、六拍及雙三拍等工作方式?！皢巍?、“雙”、“拍”的意思是：“單指定子繞組每次切換前后只有一相通電；“雙”指每次有兩相定子繞組通電；“拍”指從一種通電狀態(tài)轉到另一種通電狀態(tài)。單向晶閘管的導通條件是什么？答:導通條件是指晶閘管從阻斷到導通的條件，條件是晶閘管的陽極加上正向電壓，同時在門極加上正向電壓。晶閘管一旦導通，門極對晶閘管就不起控制作用。什

7、么是直流電動機？它有哪些優(yōu)點？答：直流電動機是一種將直流電轉換為機械能的裝置，它的最大優(yōu)點是調速性能好，可以在寬廣的范圍內實現(xiàn)無級調速；另外，它的起動轉矩大，過載能力強。直流電動機由定子和轉子兩大部分組成，在定子和轉子之間是空氣隙。什么是步進電機？答：步進電機是一種電磁式增量運動執(zhí)行元件，它可以將輸入的電脈沖信號轉換成相應的角位移或直線位移。因輸入的是脈沖信號，運動是斷續(xù)的，又稱脈沖電機或階躍電機。環(huán)形分配器的主要功能是什么？答：環(huán)形分配器的主要功能是把來自變頻信號源的脈沖序列按一定的規(guī)律分配后，經(jīng)過功率放大器的放大加到步進電機驅動電源的各項輸入端，以驅動步進電機的轉動。同時步進電機有正反轉的

8、要求，所以這種環(huán)形分配器的輸出既是周期的，又是可逆的。三、分析計算題2、解：不考慮符號，由圖1可列出下面的方程將后兩個公式帶入第一個公式，可得傳遞函數(shù)為：四、設計電路用7805設計一個輸出電壓為+7V的穩(wěn)壓電路。請您刪除一下內容，O(C_C)0謝謝！!20XX年中央電大期末復習考試小抄大全，電大期末考試必備小抄，電大考試必過小抄AfterearninghisspursinthekitchensofTheWestin,TheSheraton,SensontheBund,andasprinklingofothertop-notchvenues,SimpsonLufinallygotthechanc

9、etobecomehisownbossinNovember20XX年.Sortof.TheShanghai-bornchefmightnotactuallyownCaliforniaPizzaKitchen(CPK)butheisinsolechargeofbothkitchenandfrontof-houseatthisSinanMansions stalwart.Its certainly a responsibility to be the hcehaedfand-yea “r-oltdhe 31tells Enjoy Shanghai.thentohavetomanagetherest

10、oftherestaurantaswell,Inhotels,forexample,thesejobsarestrictlydemarcated,soitsagreatopportunitytolearnhowabusinessoperatesacrosstheboard.“ItwaatasskthatmanagementbackinsunnyCaliforniaevidentlyfelthewasreadyfor,andavoteofconfidencefromacompanythat,todate,hasopened250outletsin11countries.Andforaddedpr

11、essure,theShanghaibranchwasalsoCPKsChinadebut.reit“waFsorsuabigstep,andunlikealltheirotherAsiaoperationsthatarefranchises,theydecidedtomanageitdirectlytobeginwith,“saysSimpson.Twoyeaagoaprivatefranchiseetookoverthelease,butthelinkstoCPKheadquartersarestillstrong,withamainland-basedbrandambassadoronh

12、andtoensurethebusinessadherestoitsethosofcreating“innovative,hear-tbhakedpizzas“,asliceofPRblurbthatSimpsoninsistslivesuptothehype.“Theyareveryinnovative,“he“Theproblemwithmostfastfoodplacesisthattheyusethesamesauceoneverypizzaandjustchangethetoppings.Everyoneofour16pizzasaucesisauniquerecipethathas

13、beenformulatedtocomplementthetoppingsperfectly.“ThelargelylocalcustomerbaseevnitdlyagreesandonSaturdayandSunday,atleast,theplaceisteeming.Thekids-eat-for-freepolicyatweekendsisundoubtedlyabigdraw,aswellasisthespacioussecond-floorlayoutoverlookedbyacanopyofgreenfromFuxingParkovertheroad.Thecompanyisa

14、lsofocusingonincreasingbrandrecognitionandinrecentyearshastakenpartinoutsideeventssuchastheregularCaliforniaWeek.Still,thestaarehonestenoughtoadmitthatbusinesscouldbebetter;asgood,infact,asinCPKdssecoutletinthepopularKerryParksideshoppingmallinPudong.“Sinant been easy for any of theMansionshasreally

15、struggledtogetthenumberofvisitorsthatwereenvisagedwhenitfirstopened,andithasntenants here, “ adds Simpson.We re plaanthniirndgoutlet in the city inthe better foot traffic.20XX年,andwewillprobablychooseashoppingmallagainbecauseofThetearoomsoncefrequentedbyCocoChanelandMarcelProustareuppingsticksandcom

16、ingtoShanghai,XuJunqianvisitstheParisianoutpostwithsweettreats.Onethingthecentury-oldParisiantearoomAngelinahasshownisthatlegendaryfashiondesignerCocoChanelnotonlyhadstyleandglamorbutalsoboastedgreattasteinfood,pastriesinparticular.OneofthemostpopulartearoomsinParis,Angelinaisfamousforhavingoncebeen

17、frequentedbycelebritiessuchasChanelandwriterMarcelProust.NowAngelinahaspackedupitsFrenchambience,efficientservice,andbeautiful,comfortingdessertsandflownthemtoShanghai.Attheflagshipdine-inandtake-outspaceinShanghai,everythingmimicstheoriginaltearoomdesignedfromthebeginningofthe20thcentury,inParis,th

18、eheightof“BelleEpoque“.Thepaintingsthewall,forexample,areexactlythesameastheonethatdepictsthelandscapeofsouthernFrance,thehometownoftheowner;andthesmalltablesareintentionalimitationsoftheonesthatCocoChaneloncesatateveryafternoonforhotchocolate.Thefamoushotchocolate,knownasLAfricain,isaluxuroiusmixtu

19、reoffourtypesofcocoabeansimportedfromAfrica,blendedinParisandthenshippedtoShanghai.Itssinfullsweet,richandthickasifputtingabarofmeltingchocolatedirectlyonthetongueandthefreshwhippedcreamonthesidemakesalight,butequallygratifyingcontrast.Itisalsosoldinglassbottlesastakeaway.ThesignatureMont-Blancchest

20、nutcakeconsistsofthreeparts:thepureedchestnutontop,thevanillacreamlikestuffing,andthemeringueasbase.Getallthreelayersinonescoop,notonlyforthedifferenttexturesbutalsovariousflavorsofsweetness.Thedesserthasmaintaineditspopularityforacentury,eveninacountrylikeFrance,perhapstheworldsmostcompetitiveplace

21、fordesserts.Amuchoverlookedpairing,istheParis-NewYorkchouxpastryandN226chocolateflavoredtea.Thechouxpastryisamouthfulofairypecan-flavoredwhippedcream,whilethetea,ablendofblackteasfromChinaandCeylon,cocoaandrosepetals,offersamoresubtlefragranceofflowersandchocolate.Orderingthesetwoitems,featuringamut

22、edsweetness,makesiteasierforyoutofitintoyourlittleblackdress.Breakfast,brunch,lunchandlightsupperarealsoservedatthetearoom,“ahubofmanycultures“andtakesin“amixofdifferentstylesofFrenchcuisines“,accordingtothemanagementteam.The-semicookedfoiegrasterrine,isseductiveanddeceptive.Itsgenerouslyseatthesize

23、andshapeofatoast,whiletheactualbriochetoastisbakedintoacurvedslicedippedwithfigchutney.Theflavor,however,ishonest:strong,smoothandsublime.Andyoudontactuallyneedthetoastforcrunchiness.Thisistheseasonforhighteas,withdaintycupsoffinechinaandlittlepastriesthatappealtobothvisualandphysicalappetites.Butth

24、ereisonehighteawithadifference,andPaulineD.Lohfindsoutjustexactlywhyitisspecial.EarlGreyteaandmacaronsareallverywellforthecrucialrecuperativebreakin-betweenintensiveboutsofholidayseasonshopping.Andforthosewhoprefersavorytosweet,thereisstilltheselectionofclassicChinesesnackscalleddimsumtosatisfyandsa

25、tiate.Highteaisamealtoeatwitheyeandmouth,anin-betweenindulgencethatshouldbelightenoughnottospoildinner,butsufficientlyrobusttotaketheedgeoffthehungerthatstrikeshoursafterlunch.TheafternoonteaspecialatShang-XiattheFourSeasonsHotelPudonghasjusttherightelements.Itisapamperingmeal,withtouchesofluxurytha

26、tmakethehighteasessionatreatinitself.Wholebabyabalonesarebraisedandthentoppedonashortcrustpastryshell,asortofChineseversionoftheWesternvol-au-vent,butclassier.Evenclassieristhedimsumstapleshrimpdumplingorhargow,upgradedwiththeadditionofsliversofmidnightdarktruffles.Thisisamastertouch,andchefSimonCho

27、i,whopresidesunchallengedatShang-Xi,hasscoredawinneragain.Sweetprawnsandaromatictruffleswhatsnottolove?Hismasterfulcraftsmanshipisexhibitedinyetanotherpastryasweetpastrythatisshapedtolooklikeawalnut,butwhichyoucanputstraightintothemouth.Itcrumblesimmediately,andtheslightlysweet,nuttymorselissoeasyto

28、eatyoullprobablyreachstraightforanhoetr.Myfavoriteisthedessertthatgoesbythenameyangzhiganlu,orambrosiafromthegods.Thehotelcallsitchilledmangocreamwithsago,pomeloandbirdsneit s nsestht e ingredient thatmadewithingredientsthatresonatewitheveryfemalesoul.Itdoestastelikeambrosia,withthesweet-sourfragranceofthemangoformingthefirstlayeroftasteandsens