NOR gate - Wikipedia

The NOR gate is a digital logic gate that implements logical NOR - it behaves according to the truth table to the right. A HIGH output (1) results if both ... NORgate FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Digitallogicgate ThisarticleisaboutNORinthesenseofanelectroniclogicgate(e.g.CMOS4001).ForNORinthepurelylogicalsense,seeLogicalNOR.ForotherusesofNORorNor,seeNor(disambiguation). "4001"redirectshere.Fortheyear,see5thmillennium. Thisarticleneedsadditionalcitationsforverification.Pleasehelpimprovethisarticlebyaddingcitationstoreliablesources.Unsourcedmaterialmaybechallengedandremoved.Findsources: "NORgate" – news ·newspapers ·books ·scholar ·JSTOR(September2016)(Learnhowandwhentoremovethistemplatemessage) Input Output A B ANORB 0 0 1 0 1 0 1 0 0 1 1 0 TheNORgateisadigitallogicgatethatimplementslogicalNOR-itbehavesaccordingtothetruthtabletotheright.AHIGHoutput(1)resultsifboththeinputstothegateareLOW(0);ifoneorbothinputisHIGH(1),aLOWoutput(0)results.NORistheresultofthenegationoftheORoperator.ItcanalsoinsomesensesbeseenastheinverseofanANDgate.NORisafunctionallycompleteoperation—NORgatescanbecombinedtogenerateanyotherlogicalfunction.ItsharesthispropertywiththeNANDgate.Bycontrast,theORoperatorismonotonicasitcanonlychangeLOWtoHIGHbutnotviceversa. Inmost,butnotall,circuitimplementations,thenegationcomesforfree—includingCMOSandTTL.Insuchlogicfamilies,ORisthemorecomplicatedoperation;itmayuseaNORfollowedbyaNOT.Asignificantexceptionissomeformsofthedominologicfamily. TheoriginalApolloGuidanceComputerused4,100integratedcircuits(IC),eachonecontainingonlytwo3-inputNORgates.[1] Contents 1Symbols 2Hardwaredescriptionandpinout 2.1Availability 3Implementations 4Functionalcompleteness 5Seealso 6References Symbols[edit] TherearethreesymbolsforNORgates:theAmerican(ANSIor'military')symbolandtheIEC('European'or'rectangular')symbol,aswellasthedeprecatedDINsymbol.FormoreinformationseeLogicGateSymbols.TheANSIsymbolfortheNORgateisastandardORgatewithaninversionbubbleconnected. Thebubbleindicatesthatthefunctionoftheorgatehasbeeninverted. MIL/ANSISymbol IECSymbol DINSymbol NORFulladder Hardwaredescriptionandpinout[edit] NORGatesarebasiclogicgates,andassuchtheyarerecognisedinTTLandCMOSICs.Thestandard,4000series,CMOSICisthe4001,whichincludesfourindependent,two-input,NORgates.Thepinoutdiagramisasfollows: PinoutDiagramofa4001QuadNORDIP-formatIC 1InputA1 2InputB1 3OutputQ1 4OutputQ2 5InputB2 6InputA2 7Vss 8InputA3 9InputB3 10OutputQ3 11OutputQ4 12InputB4 13InputA4 14Vdd Availability[edit] ThesedevicesareavailablefrommostsemiconductormanufacturerssuchasFairchildSemiconductor,PhilipsorTexasInstruments.Theseareusuallyavailableinboththrough-holeDIPandSOICformat.Datasheetsarereadilyavailableinmostdatasheetdatabases. InthepopularCMOSandTTLlogicfamilies,NORgateswithupto8inputsareavailable: CMOS 4001:Quad2-inputNORgate 4025:Triple3-inputNORgate 4002:Dual4-inputNORgate 4078:Single8-inputNORgate TTL 7402:Quad2-inputNORgate 7427:Triple3-inputNORgate 7425:Dual4-inputNORgate(withstrobe,obsolete) 74260:Dual5-InputNORGate 744078:Single8-inputNORGate IntheolderRTLandECLfamilies,NORgateswereefficientandmostcommonlyused. Implementations[edit] PMOSNORgatewithloadresistor. Thediagramsaboveshowtheconstructionofa2-inputNORgateusingNMOSlogiccircuitry.Ifeitheroftheinputsishigh,thecorrespondingN-channelMOSFETisturnedonandtheoutputispulledlow;otherwisetheoutputispulledhighthroughthepull-upresistor. ThephysicallayoutofaCMOSNOR Thediagrambelowshowsa2-inputNORgateusingCMOStechnology.ThediodesandresistorsontheinputsaretoprotecttheCMOScomponentsfromdamageduetoelectrostaticdischarge(ESD)andplaynopartinthelogicalfunctionofthecircuit. UnbufferedCMOStwoinputNORgate Functionalcompleteness[edit] Mainarticle:NORlogic TheNORgatehasthepropertyoffunctionalcompleteness,whichitshareswiththeNANDgate.Thatis,anyotherlogicfunction(AND,OR,etc.)canbeimplementedusingonlyNORgates.[2]AnentireprocessorcanbecreatedusingNORgatesalone. AsNANDgatesarealsofunctionallycomplete,ifnospecificNORgatesareavailable,onecanbemadefromNANDgatesusingNANDlogic.[2] Desiredgate NANDConstruction Seealso[edit] ANDgate ORgate NOTgate NANDgate XORgate XNORgate NANDlogic Booleanalgebra(logic) Flashmemory References[edit] ^Whipple,Walt(2019).First-Hand:HackingApollo'sGuidanceComputer.EngineeringandTechnologyHistoryWiki. ^abMano,M.MorrisandCharlesR.Kime.LogicandComputerDesignFundamentals,ThirdEdition.PrenticeHall,2004.p.73. WikimediaCommonshasmediarelatedtoNORgates. vteLogicalconnectives Tautology/True  ⊤ {\displaystyle\top} Alternativedenial (NANDgate)  ↑ {\displaystyle\uparrow} Converseimplication  ← {\displaystyle\leftarrow} Implication (IMPLYgate)  → {\displaystyle\rightarrow} Disjunction (ORgate)  ∨ {\displaystyle\lor} Negation (NOTgate)  ¬ {\displaystyle\neg} Exclusiveor (XORgate)  ↮ {\displaystyle\not\leftrightarrow} Biconditional (XNORgate)  ↔ {\displaystyle\leftrightarrow} Statement (Digitalbuffer) Jointdenial (NORgate)  ↓ {\displaystyle\downarrow} Nonimplication (NIMPLYgate)  ↛ {\displaystyle\nrightarrow} Conversenonimplication  ↚ {\displaystyle\nleftarrow} Conjunction (ANDgate)  ∧ {\displaystyle\land} Contradiction/False  ⊥ {\displaystyle\bot}  Philosophyportal Retrievedfrom"https://en.wikipedia.org/w/index.php?title=NOR_gate&oldid=1094751710" Categories:LogicgatesHiddencategories:ArticleswithshortdescriptionShortdescriptionmatchesWikidataArticlesneedingadditionalreferencesfromSeptember2016AllarticlesneedingadditionalreferencesCommonscategorylinkisonWikidataPagesthatuseadeprecatedformatofthemathtags Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk English Views ReadEditViewhistory More Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Inotherprojects WikimediaCommons Languages العربيةAzərbaycancaCatalàČeštinaDeutschEestiEspañolEuskaraفارسی한국어हिन्दीLatinaLombardМакедонскиNederlands日本語PortuguêsRomânăSimpleEnglishSlovenčinaСрпски/srpskiSrpskohrvatski/српскохрватскиSuomiதமிழ்Українська粵語中文 Editlinks