电大《机电接口技术》期末考试重点复习题资料参考

1、电大机电接口技术期末考试重点复习题资料电大机电接口技术期末自测题输入电压过零，输出电压发生跳变。除此之外，输出电压保持不变。并希望输入电压大于零时输出为高电平。则应选用（A 差动型电平检测器比较器成稳压器。A 三端可调正电压输出C.固定型负电压输出一、选择题1.要求电压比较器仅在除此之外，输出电压保持不变。并希）。B同相输入过零比较器C窗口D回差电压比较器2.317为（）集B.固定型正电压输出D.三端可调负电压输出3.若希望电压比较器在输入小于+5V时输出电压为高电平，而在输入大于十5V时输出电压为低电平。则应选用（）。A反相端输入差动电平检测器B过零比较器C窗口比较器D回差电压比较器4.模拟

2、电压比较器同运算放大器的主要区别是：模拟电压比较器中的工作于（）。A.开环状态B.负反馈状态C.深度负反馈状态D高电平状态5.单向晶闸管有三个引脚：A、K和G，其中K为（）。A.阳极B.阴极C.控制极D门级6.AD202/AD204是基于（）原理的隔离放大器。A.变压器耦合B.光电隔离C.继电器隔离D,线性光电隔离7.运算放大器中的（）单元用于设置各级放大电路的静态工作点。A.输入级B.输出级C.中间级D.偏置电路8.最早出现的电动机是（）。A.直流电动机B.交流电动机C.步进电动机D.直线电动机9.三相异步电动机改变同步转速n0的方法是（）。A.调节转子电阻B.调节定子电压C.调节电源频率D

3、.调节转子电压10.L290是一种（）-F4-|_L芯片。A.功率驱动芯片B.步进电机环形分配器C.细分电路D.转速/电压变换器二、简答题1什么是光电耦合器件？光电耦合器件有什么特点？2隔离的实质是什么？有哪些常用的隔离？3SPWM的基本思想是什么？产生SPWM控制信号的方法主要有哪三种？4常用的隔离方式有哪几种?光电隔离的特点是什么?5三相步进电机的工作方式哪几种?其中“单”、“双”、“拍”各是什么意思?6单向晶闸管的导通条件是什么？7什么是直流电动机？它有哪些优点？8什么是步进电机？9环形分配器的主要功能是什么？三、分析计算题图11.写出图1所示电路的传递函数。四、设计电路1、用7805设

4、计一个输出电压为+7V的稳压电路。机电接口技术期末自测题答案一、选择题1、B2、A3、A4、A5、B6、A7、D8、A9、C10、D二、简答题1什么是光电耦合器件？光电耦合器件有什么特点？光电耦合器件将发光元件和受光元件组合在一起，通过电-光-电这种转换，利用“光”这一环节完成隔离功能，使输入和输出在电气上是完全隔离的。根据受光元件的不同可分为晶体管输出型和晶闸管输出型两类。光电耦合器具有三个特点：信号传递采取电-光-电的形式，能够避免输出端对输入端可能产生的反馈和干扰，抑制噪声干扰能力强；具有耐用、可靠性高和速度快等优点。2隔离的实质是什么？有哪些常用的隔离？答：隔离的实质是把引进的干扰通道

5、切断，从而达到隔离现场干扰的目的。测控装置与现场信号之间、弱电和强电之间，常用的隔离方式有光电隔离、继电器隔离、变压器隔离、隔离放大器等。另外，在布线上也应该注意隔离。SPWM的基本思想是什么？产生SPWM控制信号的方法主要有哪三种？答：SPWM的基本思想是：保持输出脉冲电压幅度不变，用调节脉冲的宽度和间隔实现其平均值接近正弦（同时改变U和f）。将此脉冲电压加到电机上，所得到的电流波形接近于正弦波。就硬件方面讲，产生SPWM控制信号的方法主要有三种：1）采用微处理器。2）采用专用大规模集成电路。3）采用微处理器和专用大规模集成电路相结合。常用的隔离方式有哪几种?光电隔离的特点是什么?答：常用的

6、隔离方式有光电隔离、继电器隔离、变压器隔离、隔离放大器等。光电隔离是以光为媒介传输信号的器件，输入和输出在电气上是完全隔离的。具有较高的电气隔离和抗干扰能力。三相步进电机的工作方式哪几种?其中“单”、“双”、“拍”各是什么意思?答：三相步进电机一般有单三拍、六拍及双三拍等工作方式。“单”、“双”、“拍”的意思是：“单指定子绕组每次切换前后只有一相通电；“双”指每次有两相定子绕组通电；“拍”指从一种通电状态转到另一种通电状态。单向晶闸管的导通条件是什么？答:导通条件是指晶闸管从阻断到导通的条件，条件是晶闸管的阳极加上正向电压，同时在门极加上正向电压。晶闸管一旦导通，门极对晶闸管就不起控制作用。什

7、么是直流电动机？它有哪些优点？答：直流电动机是一种将直流电转换为机械能的装置，它的最大优点是调速性能好，可以在宽广的范围内实现无级调速；另外，它的起动转矩大，过载能力强。直流电动机由定子和转子两大部分组成，在定子和转子之间是空气隙。什么是步进电机？答：步进电机是一种电磁式增量运动执行元件，它可以将输入的电脉冲信号转换成相应的角位移或直线位移。因输入的是脉冲信号，运动是断续的，又称脉冲电机或阶跃电机。环形分配器的主要功能是什么？答：环形分配器的主要功能是把来自变频信号源的脉冲序列按一定的规律分配后，经过功率放大器的放大加到步进电机驱动电源的各项输入端，以驱动步进电机的转动。同时步进电机有正反转的

8、要求，所以这种环形分配器的输出既是周期的，又是可逆的。三、分析计算题2、解：不考虑符号，由图1可列出下面的方程将后两个公式带入第一个公式，可得传递函数为：四、设计电路用7805设计一个输出电压为+7V的稳压电路。请您删除一下内容，O(C_C)0谢谢！!20XX年中央电大期末复习考试小抄大全，电大期末考试必备小抄，电大考试必过小抄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