2015年电大电工电子技术试题（一）期末复习考试资料

电工电子技术模拟题（一）一、填空题每空2分，共20分1任意时刻，流入电路中任一（节点）的电流之和恒等于（流出）该节点的电流之和。2放大电路的信号源内电阻（RS）越高，电路的电压放大倍数（越小）。3对于TTL门电路，输出为（高电位）时，带负载的能力弱。输出为（低电位）时，带负载的能力强。4磁力线越密表示磁场（越强）。5描述逻辑功能的方法有（真值表）、（逻辑图）、（表达式）。二、单项选择题（每题4分，共20分）1、图1所示电路中U为（A）。A30VB10VC40V2、图2所示电路中，电源电压不变，而频率升高，各灯泡的亮度变化是（B）。A灯泡A变亮B灯泡B变亮C灯泡C变亮3、图3所示变压器，已知原方N1300匝，R8，则从原方看入的电阻RI是72，则变压器副方绕组N2为（C）。A200匝B300匝C100匝4、稳压二极管是利用其工作在（C）时电压变化极小的特性，使两端电压得到稳定的。A正向B反向C反向击穿5、放大电路引入电压并联负反馈，可以使输入电阻（B）。A增大B减小C不变三、计算题（每题15分，共30分）1图31所示电路可用来测量电源的数值及其内阻，图中标出的U和R0组成某实际电压源。已知R126，R255，当开关K1闭合，K2打开时，电流表读数为2A；打开K1，闭合K2后，读U2A1545V图1CBALCRU图2N2N1图3RRI数为1A，试求U和R0。解K1闭合，K2打开，有I1（R0R1）UK1打开，K2闭合，有I2（R0R2）U联立上两式，得出U58V，R0032、有一电感线圈，当接在电压为40V的直流电源上时，测得线圈电流为4A。当接于电压为220V、频率为50HZ的正弦交流电源时，测得电流为10A，求线圈电阻与电感。解直流电源作用时XLL0，R40/410交流电源作用时Z22IU102XL196RZ210L624MHF2四、简答题（每题5分，共30分）1、恒压源的性质是什么恒压源的性质为（1）它的输出电压始终是恒定的，不受输出电流的影响；（2）通过它的电流不由它本身决定，由与之相连的负载电阻决定。2、简述RLC串联电路产生串联谐振的特点（1）电路的阻抗最小并呈电阻性。（2）电路中的电流最大。（3）XLXC，串联谐振可在电容和电感两端产生高电压。图31UK2K1R2R1R03、如果需要电动机连续运行，那么对于三相异步电动机功率的选择要注意什么功率选择应该以产生机械所需要的实际功率为依据。选择的过大，效率和功率因数会很低，不经济。选择的过小，电动机长时间工作在外额定过载状态下，不仅不能保证正常工作，还可能造成电动机损坏。4、基本放大电路的组成原则是什么答1电路中既有直流通路，又有交流通路。2电路由线性元件和非线性器件组成。3三极管工作在放大状态，保证信号失真不超过允许范围。5、引入电压串联负反馈和电流并联负反馈，对放大电路的输入、输出电阻分别有什么影响答引入电压串联负反馈，会使输入电阻增大，输出电阻减小；引入电流并联负反馈，会使输入电阻减小，输出电阻增大。请您删除一下内容，O_O谢谢2015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,ANDASPRINKLINGOFOTHERTOPNOTCHVENUES,SIMPSONLUFINALLYGOTTHECHANCETOBECOMEHISOWNBOSSINNOVEMBER2010SORTOFTHESHANGHAIBORNCHEFMIGHTNOTACTUALLYOWNCALIFORNIAPIZZAKITCHENCPKBUTHEISINSOLECHARGEOFBOTHKITCHENANDFRONTOFHOUSEATTHISSINANMANSIONSSTALWART“ITSCERTAINLYARESPONSIBILITYTOBETHEHEADCHEF,ANDTHENTOHAVETOMANAGETHERESTOFTHERESTAURANTASWELL,“THE31YEAROLDTELLSENJOYSHANGHAI“INHOTELS,FOREXAMPLE,THESEJOBSARESTRICTLYDEMARCATED,SOITSAGREATOPPORTUNITYTOLEARNHOWABUSINESSOPERATESACROSSTHEBOARD“ITWASATASKTHATMANAGEMENTBACKINSUNNYCALIFORNIAEVIDENTLYFELTHEWASREADYFOR,ANDAVOTEOFCONFIDENCEFROMACOMPANYTHAT,TODATE,HASOPENED250OUTLETSIN11COUNTRIESANDFORADDEDPRESSURE,THESHANGHAIBRANCHWASALSOCPKSCHINADEBUT“FORSUREITWASABIGSTEP,ANDUNLIKEALLTHEIROTHERASIAOPERATIONSTHATAREFRANCHISES,THEYDECIDEDTOMANAGEITDIRECTLYTOBEGINWITH,“SAYSSIMPSONTWOYEARSAGOAPRIVATEFRANCHISEETOOKOVERTHELEASE,BUTTHELINKSTOCPKHEADQUARTERSARESTILLSTRONG,WITHAMAINLANDBASEDBRANDAMBASSADORONHANDTOENSURETHEBUSINESSADHERESTOITSETHOSOFCREATING“INNOVATIVE,HEARTHBAKEDPIZZAS“,ASLICEOFPRBLURBTHATSIMPSONINSISTSLIVESUPTOTHEHYPE“THEYAREVERYINNOVATIVE,“HESAYS“THEPROBLEMWITHMOSTFASTFOODPLACESISTHATTHEYUSETHESAMESAUCEONEVERYPIZZAANDJUSTCHANGETHETOPPINGSEVERYONEOFOUR16PIZZASAUCESISAUNIQUERECIPETHATHASBEENFORMULATEDTOCOMPLEMENTTHETOPPINGSPERFECTLY“THELARGELYLOCALCUSTOMERBASEEVIDENTLYAGREESANDONSATURDAYANDSUNDAY,ATLEAST,THEPLACEISTEEMINGTHEKIDSEATFORFREEPOLICYATWEEKENDSISUNDOUBTEDLYABIGDRAW,ASWELLASISTHESPACIOUSSECONDFLOORLAYOUTOVERLOOKEDBYACANOPYOFGREENFROMFUXINGPARKOVERTHEROADTHECOMPANYISALSOFOCUSINGONINCREASINGBRANDRECOGNITIONANDINRECENTYEARSHASTAKENPARTINOUTSIDEEVENTSSUCHASTHEREGULARCALIFORNIAWEEKSTILL,THESTAAREHONESTENOUGHTOADMITTHATBUSINESSCOULDBEBETTERASGOOD,INFACT,ASINCPKSSECONDOUTLETINTHEPOPULARKERRYPARKSIDESHOPPINGMALLINPUDONG“SINANMANSIONSHASREALLYSTRUGGLEDTOGETTHENUMBEROFVISITORSTHATWEREENVISAGEDWHENITFIRSTOPENED,ANDITHASNTBEENEASYFORANYOFTHETENANTSHERE,“ADDSSIMPSON“WEREPLANNINGATHIRDOUTLETINTHECITYIN2015,ANDWEWILLPROBABLYCHOOSEASHOPPINGMALLAGAINBECAUSEOFTHEBETTERFOOTTRAFFIC“THETEAROOMSONCEFREQUENTEDBYCOCOCHANELANDMARCELPROUSTAREUPPINGSTICKSANDCOMINGTOSHANGHAI,XUJUNQIANVISITSTHEPARISIANOUTPOSTWITHSWEETTREATSONETHINGTHECENTURYOLDPARISIANTEAROOMANGELINAHASSHOWNISTHATLEGENDARYFASHIONDESIGNERCOCOCHANELNOTONLYHADSTYLEANDGLAMORBUTALSOBOASTEDGREATTASTEINFOOD,PASTRIESINPARTICULARONEOFTHEMOSTPOPULARTEAROOMSINPARIS,ANGELINAISFAMOUSFORHAVINGONCEBEENFREQUENTEDBYCELEBRITIESSUCHASCHANELANDWRITERMARCELPROUSTNOWANGELINAHASPACKEDUPITSFRENCHAMBIENCE,EFFICIENTSERVICE,ANDBEAUTIFUL,COMFORTINGDESSERTSANDFLOWNTHEMTOSHANGHAIATTHEFLAGSHIPDINEINANDTAKEOUTSPACEINSHANGHAI,EVERYTHINGMIMICSTHEORIGINALTEAROOMDESIGNEDFROMTHEBEGINNINGOFTHE20THCENTURY,INPARIS,THEHEIGHTOF“BELLEEPOQUE“THEPAINTINGSONTHEWALL,FOREXAMPLE,AREEXACTLYTHESAMEASTHEONETHATDEPICTSTHELANDSCAPEOFSOUTHERNFRANCE,THEHOMETOWNOFTHEOWNERANDTHESMALLTABLESAREINTENTIONALIMITATIONSOFTHEONESTHATCOCOCHANELONCESATATEVERYAFTERNOONFORHOTCHOCOLATETHEFAMOUSHOTCHOCOLATE,KNOWNASLAFRICAIN,ISALUXURIOUSMIXTUREOFFOURTYPESOFCOCOABEANSIMPORTEDFROMAFRICA,BLENDEDINPARISANDTHENSHIPPEDTOSHANGHAIITSSINFULLYSWEET,RICHANDTHICKASIFPUTTINGABAROFMELTINGCHOCOLATEDIRECTLYONTHETONGUEANDTHEFRESHWHIPPEDCREAMONTHESIDEMAKESALIGHT,BUTEQUALLYGRATIFYINGCONTRASTITISALSOSOLDINGLASSBOTTLESASTAKEAWAYTHESIGNATUREMONTBLANCCHESTNUTCAKECONSISTSOFTHREEPARTSTHEPUREEDCHESTNUTONTOP,THEVANILLACREAMLIKESTUFFING,ANDTHEMERINGUEASBASEGETALLTHREELAYERSINONESCOOP,NOTONLYFORTHEDIFFERENTTEXTURESBUTALSOVARIOUSFLAVORSOFSWEETNESSTHEDESSERTHASMAINTAINEDITSPOPULARITYFORACENTURY,EVENINACOUNTRYLIKEFRANCE,PERHAPSTHEWORLDSMOSTCOMPETITIVEPLACEFORDESSERTSAMUCHOVERLOOKEDPAIRING,ISTHEPARISNEWYORKCHOUXPASTRYANDN226CHOCOLATEFLAVOREDTEATHECHOUXPASTRYISAMOUTHFULOFAIRYPECANFLAVOREDWHIPPEDCREAM,WHILETHETEA,ABLENDOFBLACKTEASFROMCHINAANDCEYLON,COCOAANDROSEPETALS,OFFERSAMORESUBTLEFRAGRANCEOFFLOWERSANDCHOCOLATEORDERINGTHESETWOITEMS,FEATURINGAMUTEDSWEETNESS,MAKESITEASIERFORYOUTOFITINTOYOURLITTLEBLACKDRESSBREAKFAST,BRUNCH,LUNCHANDLIGHTSUPPERAREALSOSERVEDATTHETEAROOM,“AHUBOFMANYCULTURES“ANDTAKESIN“AMIXOFDIFFERENTSTYLESOFFRENCHCUISINES“,ACCORDINGTOTHEMANAGEMENTTEAMTHESEMICOOKEDFOIEGRASTERRINE,ISSEDUCTIVEANDDECEPTIVEITSGENEROUSLYSERVEDATTHESIZEANDSHAPEOFATOAST,WHILETHEACTUALBRIOCHETOASTISBAKEDINTOACURVEDSLICEDIPPEDWITHFIGCHUTNEYTHEFLAVOR,HOWEVER,ISHONESTSTRONG,SMOOTHANDSUBLIMEANDYOUDONTACTUALLYNEEDTHETOASTFORCRUNCHINESSTHISISTHESEASONFORHIGHTEAS,WITHDAINTYCUPSOFFINECHINAANDLITTLEPASTRIESTHATAPPEALTOBOTHVISUALANDPHYSICALAPPETITESBUTTHEREISONEHIGHTEAWITHADIFFERENCE,ANDPAULINEDLOHFINDSOUTJUSTEXACTLYWHYITISSPECIALEARLGREYTEAANDMACARONSAREALLVERYWELLFORTHECRUCIALRECUPERATIVEBREAKINBETWEENINTENSIVEBOUTSOFHOLIDAYSEASONSHOPPINGANDFORTHOSEWHOPREFERSAVORYTOSWEET,THEREISSTILLTHESELECTIONOFCLASSICCHINESESNACKSCALLEDDIMSUMTOSATISFYANDSATIATEHIGHTEAISAMEALTOEATWITHEYEANDMOUTH,ANINBETWEENINDULGENCETHATSHOULDBELIGHTENOUGHNOTTOSPOILDINNER,BUTSUFFICIENTLYROBUSTTOTAKETHEEDGEOFFTHEHUNGERTHATSTRIKESHOURSAFTERLUNCHTHEAFTERNOONTEASPECIALATSHANGXIATTHEFOURSEASONSHOTELPUDONGHASJUSTTHERIGHTELEMENTSITISAPAMPERINGMEAL,WITHTOUCHESOFLUXURYTHATMAKETHEHIGHTEASESSIONATREATINITSELFWHOLEBABYABALONESAREBRAISEDANDTHENTOPPEDONASHORTCRUSTPASTRYSHELL,ASORTOFCHINESEVERSIONOFTHEWESTERNVOLAUVENT,BUTCLASSIEREVENCLASSIERISTHEDIMSUMSTAPLESHRIMPDUMPLINGORHARGOW,UPGRADEDWITHTHEADDITIONOFSLIVERSOFMIDNIGHTDARKTRUFFLESTHISISAMASTERTOUCH,ANDCHEFSIMONCHOI,WHOPRESIDESUNCHALLENGEDATSHANGXI,HASSCOREDAWINNERAGAINSWEETPRAWNSANDAROMATICTRUFFLESWHATSNOTTOLOVEHISMASTERFULCRAFTSMANSHIPISEXHIBITEDINYETANOTHERPASTRYASWEETPASTRYTHATISSHAPEDTOLOOKLIKEAWALNUT,BUTWHICHYOUCANPUTSTRAIGHTINTOTHEMOUTHITCRUMBLESIMMEDIATELY,ANDTHESLIGHTLYSWEET,NUTTYMORSELISSOEASYTOEATYOULLPROBABLYREACHSTRAIGHTFORANOTHERMYFAVORITEISTHEDESSERTTHATGOESBYTHENAMEYANGZHIGANLU,ORAMBROSIAFROMTHEGODSTHEHOTELCALLSITCHILLEDMANGOCREAMWITHSAGO,POMELOANDBIRDSNESTMADEWITHINGREDIENTSTHATRESONATEWITHEVERYFEMALESOULITDOESTASTELIKEAMBROSIA,WITHTHESWEETSOURFRAGRANCEOFTHEMANGOFORMINGTHEFIRSTLAYEROFTASTEANDSENSATION,ANDTHEPOMELOSACSANDSAGOPEARLSPROVIDINGTHETACTILECONTRASTTHEBIRDSNESTITSTHEINGREDIENTTHATGILDSTHELILY,SINCEITISSUPPO