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电大《机电接口技术》期末考试重点复习题资料参考电大机电接口技术期末自测题
一、选择题
1.要求电压比较器仅在输入电压过零,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B.同相输入过零比较器C.窗口比较器D.回差电压比较器
2.317为()集成稳压器A.三端可调正电压输出B.固定型正电压输出C.固定型负电压输出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+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.调节转子电压
10.L290是一种芯片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?3.SPWM的基本思想是什么?产生SPWM控制___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、B
2、A
3、A
4、A
5、B
6、A
7、D
8、A
9、C
10、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
①___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,
②抑制噪声干扰能力强;
③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切断,从而达到隔离现场干扰的目的测控装置与现场___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3.SPWM的基本思想是什么?产生SPWM控制___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___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4.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___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6.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7.什么是直流电动机?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8.什么是步进电机?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___转换成相应的角位移或直线位移因输入的是脉冲___,运动是断续的,又称脉冲电机或阶跃电机9.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变频___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∩_∩O谢谢!!!xx年___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AfterearninghisspursinthekitchensofTheWestinTheSheratonSensontheBundandasprinklingofothertop-notchvenuesSimpsonLufinallygotthechan___tobeehisownbossinNovemberxx.Sortof.TheShanghai-bornchefmightnotactuallyownCaliforniaPizzaKitchenCPKbutheisinsolechargeofbothkitchenandfrontof-houseatthisSinanMansions'stalwart.“It’s___rtainlyaresponsibilitytobetheheadchefandthentohaveto___nagetherestoftherestaurantaswell“the31-year-old___sEnjoyShanghai.“Inhotelsforexamplethesejobsarestrictlyde___rcatedsoit’sagreatopportunitytolearnhowabusinessoperatesacrosstheboard.“Itwasataskthat___nagementbackinsunnyCaliforniaevidentlyfelthewasreadyforandavoteofconfiden___fromapanythattodatehasopened250outletsin11countries.AndforaddedpressuretheShanghaibranchwasalsoCPK’sChinadebut.“ForsureitwasabigstepandunlikealltheirotherAsiaoperationsthatarefranchisestheydecidedto___nageitdirectlytobeginwith“saysSimpson.TwoyearsagoaprivatefranchiseetookovertheleasebutthelinkstoCPKheadquartersarestillstrongwitha___inland-based'brandambassador’onhandtoensurethebusinessadherestoitsethosofcreating“innovativehearth-bakedpizzas“asli___ofPRblurbthatSimpsoninsistslivesuptothehype.“Theyareveryinnovative“hesays.“Theproblemwithmostfastfoodpla___sisthattheyusethesamesau___oneverypizzaandjustchangethetoppings.Everyoneofour16pizzasau___sisauniquerecipethathasbeenformulatedtoplementthetoppingsperfectly.“ThelargelylocalcustomerbaseevidentlyagreesandonSaturdayandSundayatleastthepla___isteeming.Thekids-eat-for-freepolicyatweekendsisundoubtedlyabigdrawaswellasisthespacioussecond-floorlayoutoverlookedbyacanopyofgreenfromFuxingParkovertheroad.Thepanyisalsofocusingonincreasingbrandrecognitionandinre___ntyearshastakenpartinoutsideeventssuchastheregularCaliforniaWeek.Stillthestaarehonestenoughtoadmitthatbusinesscouldbebetter;asgoodinfactasinCPK’ssecondoutletinthepopularKerryParksideshopping___llinPudong.“SinanMansionshasreallystruggledtogetthenumberofvisitorsthatwereenvisagedwhenitfirstopenedandithasn’tbeeneasyforanyofthetenantshere“addsSimpson.“We’replanningathirdoutletinthecityinxxandwewillprobablychooseashopping___llagainbecauseofthebetterfoottraffic.“Thetearoomson___frequentedbyCocoChanelandMar___lProustareuppingsticksandingtoShanghaiXuJunqianvisitstheParisianoutpostwithsweettreats.Onethingthe___ntury-oldParisiantearoomAngelinahasshownisthatlegendaryfashiondesignerCocoChanelnotonlyhadstyleandglamorbutalsoboastedgreattasteinfoodpastriesinparticular.OneofthemostpopulartearoomsinParisAngelinaisfamousforhavingon___beenfrequentedby___lebritiessuchasChanelandwriterMar___lProust.NowAngelinahaspackedupitsFrenchambien___efficientservi___andbeautifulfortingdessertsandflownthemtoShanghai.Attheflagshipdine-inandtake-outspa___inShanghaieverythingmimicstheoriginaltearoomdesignedfromthebeginningofthe20th___nturyinParistheheightof“BelleEpoque“.ThepaintingsonthewallforexampleareexactlythesameastheonethatdepictsthelandscapeofsouthernFran___thehometownoftheowner;andthes___lltablesareintentionalimitationsoftheonesthatCocoChanelon___satateveryafternoonforhotchocolate.ThefamoushotchocolateknownasL’AfricainisaluxuriousmixtureoffourtypesofcocoabeansimportedfromAfricablendedinParisandthenshippedtoShanghai.It’ssinfullysweetrichandthickasifputtingabarofmeltingchocolatedirectlyonthetongueandthefreshwhippedcreamontheside___kesalightbutequallygratifyingcontrast.Itisalsosoldinglassbottlesastakeaway.ThesignatureMont-Blancchestnutcakeconsistsofthreeparts:thepureedchestnutontopthevanillacreamlikestuffingandthemeringueasbase.Getallthreelayersinonescoopnotonlyforthedifferenttexturesbutalsovariousflavorsofsweetness.Thedesserthas___intaineditspopularityfora___nturyeveninacountrylikeFran___perhapstheworld’smostpetitivepla___fordesserts.AmuchoverlookedpairingistheParis-NewYorkchouxpastryandN226chocolateflavoredtea.Thechouxpastryisamouthfulofairypecan-flavoredwhippedcreamwhiletheteaablendofblackteasfromChinaandCeyloncocoaandrosepetalsoffersamoresubtlefragran___offlowersandchocolate.Orderingthesetwoitemsfeaturingamutedsweetness___kesiteasierforyoutofitintoyourlittleblackdress.Breakfastbrunchlunchandlightsupperarealsoservedatthetearoom“ahubof___nycultures“andtakesin“amixofdifferentstylesofFrenchcuisines“aordingtothe___nagementteam.Thesemi-cookedfoiegrasterrineisseductiveandde___ptive.It’sgenerouslyservedatthesizeandshapeofatoastwhiletheactualbriochetoastisbakedintoacurvedsli___dippedwithfigchutney.Theflavorhoweverishonest:strong___oothandsublime.Andyoudon’tactuallyneedthetoastforcrunchiness.Thisistheseasonforhighteaswithdaintycupsoffinechinaandlittlepastriesthatappealtobothvisualandphysicalappetites.Butthereisonehighteawithadifferen___andPaulineD.Lohfindsoutjustexactlywhyitisspecial.EarlGreyteaand___caronsareallverywellforthecrucialrecuperativebreakin-betweenintensiveboutsofholidayseasonshopping.AndforthosewhoprefersavorytosweetthereisstilltheselectionofclassicChinesesnackscalleddimsumtosatisfyandsatiate.Highteaisamealtoeatwitheyeandmouthanin-betweenindulgen___thatshouldbelightenoughnottospoildinnerbutsufficientlyrobusttotaketheedgeoffthehungerthatstrikeshoursafterlunch.TheafternoonteaspecialatShang-XiattheFourSeasonsHotelPudonghasjusttherightelements.Itisapamperingmealwithtouchesofluxurythat___kethehighteasessionatreatinitself.WholebabyabalonesarebraisedandthentoppedonashortcrustpastryshellasortofChineseversionoftheWesternvol-au-ventbutclassier.Evenclassieristhedimsumstapleshrimpdumplingorhargowupgradedwiththeadditionofsliversofmidnightdarktruffles.Thisisa___stertouchandchefSimonChoiwhopresidesunchallengedatShang-Xihasscoredawinneragain.Sweetprawnsandaro___tictruffles—what’snottoloveHis___sterfulcrafts___nshipisexhibitedinyetanotherpastry—asweetpastrythatisshapedtolooklikeawalnutbutwhichyoucanputstraightintothemouth.Itcrumblesimmediatelyandtheslightlysweetnuttymorselissoeasytoeatyou’llprobablyreachstraightforanother.Myfavoriteisthedessertthatgoesbythenameyangzhiganluorambrosiafromthegods.Thehotelcallsitchilled___ngocreamwithsagopomeloandbird’snest–___dewithingre___ntsthatresonatewitheveryfe___lesoul.Itdoestastelikeambrosiawiththesweet-sourfragran___ofthe___ngoformingthefirstlayeroftasteandsensationandthepomelosacsandsagopearlsprovidingthetactilecontrast.Thebird’snest—it’stheingre___ntthatgildsthelilysin___itissupposedtonourishandnurtureaperfectplexion.Forthoseunfamiliarwiththisexoticingre___ntthebird’snestisnotabundleoftwigsbutisinsteadthedriedsecretionthatcaveswiftsusetobuildtheirnest.Technicallyit’sbirdsalivabuttheChinesebelievethatithascollagen-boostingpropertiesessentialtobeauty.Tomeitjusttastesgoodaddingaslightgelatinouscrunchtothebackoftheteeth.ThereisalsoabakedmushroompuffpastrythatincludesthehighlyprizedMatsutakeorpinemushroom.Youalsogetachoi___ofteasbutIstronglyremendtheagedPu’erfromYunnanprovin___.Itisamellowteathatwillgoperfectlywiththerichlittlenuggetsandwillwarmyouuponacoldafternoon.IncidentallythegeneralguideisgreenteasuchasLong___gorDragonwellforthehotseasonsemi-fermentedteaslikeWu-longorIronBuddhaforautumnandmorewarmingteaslikePu’erforwinter.TheShang-Xiafternoonteacosts228yuan$37perpersonand388yuanforthemoreopule模板内容仅供参考。