Universal gates-NOR Gate - Electronics Hub

NOR gate is the logic gate and is one of the universal gates . NOR gate is used to construct the basic gates similar to AND gate. Home Logicgates Universalgates-NORGate July9,2015 By Administrator NORgateisthelogicgateandisoneoftheuniversalgates.NORgateisusedtoconstructthebasicgatessimilartoANDgate.BycombiningNOTgateandORgate,NORgatecanbeconstructed.TheoutputofNORgateisreversalofORgate.Generally,NORgatehave2inputs,let’ssayXandY,andoneoutputZ. Outline NORGateLogicSymbolNORGateTruthtable2-InputTransistorNORGatePulsedoperationUniversalNORGate3-InputNORgateTruthTable4-InputNORgateCommonlyavailableTTLandCMOSlogicNORgateIC’s7402Quad2-inputNORGateIC PinDescriptionNORGateApplications NORGateLogicSymbol BelowfigureshowstheNORgatelogicsymbol MathematicalexpressionforNANDgateoperationisgivenasZ=(X+Y)̅.Where,bar“̅“representsthereverseoperation. NORGateTruthtable BelowisNORgatetruthtable.ItshowsthatNORgateoutputslogichighvalueifboththeinputsareatlowlogiclevel.Thisproduceslogiclowvalueifanyofitsinputsisinhighlogiclevel. Backtotop 2-InputTransistorNORGate IntwoinputNORgatetwotransistorsareusedtodesignaNORgate.Acircuitdrivingvoltageof+6voltsisconnectedtothecollectoroffirsttransistor.Thesamesupplyvoltagewillbeparallellyconnectedtothecollectorofsecondtransistoralso.ConnecttworesistorsastheinputsofNORgate(eachof10K).Theemittersoftwotransistorsarecollectivelyconnectedtoground.Theoutputiscollectedatthenodeofsupplyvoltage,resistorandcollectoroffirsttransistor. The2-inputNORlogicgatedesignedbyusingtwotransistorsisshownbelow. ThereisanotherdesignmethodavailableforNORgatei.e.singletransistordesignedNORgate.Here,thebaseofthetransistorissupplieswithparallellyconnectedtwoinputs,throughresistors.Theemitterisconnectedtogroundandthecollectorisconnectedtothecircuitdrivingvoltage(supplyvoltage)of+6Volts.Outputiscollectedatthecollectorendofthetransistor.Observethebelowdiagram. ThisisanalternativewayofachievingNORlogicgate. Pulsedoperation Ifweapply2differentclocksignalsastheinputsofNORgateXandY,thentheoutputoftheNORgatewillbeasshownbelow(X,YareinputsandZisoutput) Ifweobservetheaboveclocksignals,wecansaythatwhenbothinputsarehigh,thentheoutputoftheNORgateisLOWandtheLOWoutputstatecontinuedforeveryinputlogiclowlevel.Attheendoftheclockpulses,theoutputbecomeshighasboththeinputsofNORgatetheinputsarelow. Backtotop UniversalNORGate NORlogicgateiscalledasthe“Universallogicgate”.Thisgatecanfunctionasanyofthebasiclogicgatesbyjustmakingsomechangesatitsinputside.Mostly,wepreferNANDgatesoverNORgatesfordesigningtheotherbasiclogicgates.Let’sseehowwecandesignothergatesbyusingNORgate. BasicLogicGatesusingonlyNORGates WecandesignbasiclogicgatessuchasAND,OR,NOTgates.Let’sseehowaNORgatecanperformallthe3typesoffunctioning. Backtotop 3-InputNORgate MultiinputNORgatecanbedesignedbyconnectingotherlogicgatesatitsinputside.Let’sseethelogicsymbolandtruthtableof3–inputNORgate.ThereisnochangeinBooleanexpressionwithchangeinnumberofinputs.TheoutputofNORgateistheinverseofadditionofNORinputs. 3-InputNORgatesymbol TheBooleanexpressionforthe3-inputNORgateisQ=(A+B+C)̅ TruthTable Thetruthtableof3–inputNORgateisgivenbelow Theoutputofthe3inputNORgateisLOWwhenallthe3inputsareHIGHanditwillbeHIGHforallothercombinationsofinputs. Backtotop 4-InputNORgate Similarto3-inputNORgates,wecanalsodesign4-inputNORgate. ItsBooleanexpressionis  Backtotop CommonlyavailableTTLandCMOSlogicNORgateIC’s ListofICsofallTTLandCMOSlogicNORgatesaregivenbelow SomeofthemostusedNORgateICsare 7402Quad2-inputNORGateIC       PinDescription   Backtotop NORGateApplications LogicNORgatecanbeusedtoconstructEX-ORgatesandsomeotherrealtimeapplications.Oneofitsrealtimeapplicationsis‘Mixertank’.Itisexplainedbelow. Ifyouobservethebelowdiagram,weusea3-inputNORgatetocontroltheflowofingredientsofamixertank.DifferentkindsofingredientsarestoredinseparatecylindricalHooper.Acapacitiveproximityswitchisarrangedoutsideofeachcylinder,atitsbottom.Thisistodetecttheamountorlevelofingredient. Whentheingredientscomedowntothesensorlevel,thecylinderproducesHIGHlevellogicoutput.Theingredientlevelhigherthanthesensorwillconsideraslowlogiclevel(0).Whenalltheingredientscomesdowntothesensorlevel,thenallinputsoftheNORgatewillbecomeHIGH. Whenalltheingredientscomesdowntothesensorlevel,theoutputofNORgatewillbecomeHIGH.ThisoutputisconnectedtothePowerconverterandthispowerconverterisconnectedtotheMotot(tomixtheingredients).TheHIGHoutputoftheNORlogicgateactivatesthepowerconverterandactivatesthemotor,makingthemotortorunandmixalltheingredients. Backtotop RelatedPosts:LogicSymbolsforBasicLogicGates(OR,AND,NOT,NAND,…ImplementationofBooleanFunctionsusingLogicGatesExclusiveORGate(XORGate)ParityGeneratorandParityCheckHalfAdderandFullAdderCircuitsDesignofTFlipFlop|CircuitusingSR,JKandD… LeaveaReplyCancelreplyYouremailaddresswillnotbepublished.Requiredfieldsaremarked*Comment*Name* Email* Website Δ Menu Learn Tutorials DIY ProductReviews Guides&Howto About