Electronics notes (Digital)

Electronicsnotes(Digital)(pmsomething3009ondiscordifthereareanyerrors)Chapter Content Examples Chapter10:IntroductiontoDigitalElectronics AnaloguequantitiesvarycontinuouslywhileDigitalquantitiesvaryinsteps Howtodifferentiatebetweenanalogueanddigitalsignals:Analoguesignals:HascontinuouslyvaryingVoltagelevelsDigitalsignals:Onlyhas2distinctvoltagelevels(HIGHorLOWonly)(HIGHreferstoLogic1state(+5V),LOWreferstoLogic0state(0V)) Analoguesignals Digitalsignals LogicSwitches Pull-Upswitch: (Pull-Upresistorwithaswitchbelow)Whenswitchisclosed,outputisLogic0(0V)Whenswitchisopen,outputisLogic1(+5V) Pull-Upswitchwhenclosed: Pull-Upswitchwhenopened:

Pull-Downswitch: (Pull-Downresistorwithaswitchabove)Whenswitchisclosed,outputisLogic0(0V)Whenswitchisopen,outputisLogic1(+5V) *ResistorinPull-Up/Pull-Downswitchareusually10㏀ Resistorisneededifnotthelogicswitchwillproducean‘floating’outputwhenopen(BadasitcanpickupunwantedelectricalsignalsandtakeonLogic0orLogic1inaunpredictableway) Pull-Downswitchwhenclosed: Pull-Downswitchwhenopened: Advantages/DisadvantagesofusingDigitalsystemsoverAnaloguesystems Advantages:- Lessaffectedbyelectricalinterference(duetofairlylargedifferencebetweenvoltagelevels),cantellLogic1apartfromLogic0aslongasitisnottoobadlydistorted- Signalscanberestoredtooriginalconditionviarepeaters(cantraveloverlongdistancesandismorereliable)- Easiertodesignduetoonlyhaving2voltagelevels- Easiertostoreinformation(asitisstoredasaseriesof0sand1s)

- Largenumberofdigitalcomponentscanbesqueezedintosmallareaofsemiconductormaterial(savecosts) Disadvantages:- AdditionalstepsareneededtoconvertbetweenAnalogueandDigitalsignals(manyquantitiesinourdailylivessuchastemperatureandlightintensityareanaloguequantities) HowtorepresentanddisplayvaluesinDigitalForm DecimalSystem:Madeupof10digits(0-9)Positionofadigitdeterminesitsplacevalue BinarySystem:Madeupof2digits(bits)(0and1)PositionofabitdeterminesitsplacevalueHighestplacevalue-MostSignificantBit(MSB)Lowestplacevalue-LeastSignificantBit(LSB) *youcanpresscalculatortoskipthecalculationpartsinconvertingdecimaltobinaryandViceVersa Binary-codeddecimal(BCD):Usesgroupsof4-bitbinarycodetorepresentthedigitsofadecimalnumber(Codingsystem)Decimalnumber BCDequivalent 4 0100 98 10011000 163 000101100011 ConvertingbetweenBinary,DecimalsystemsandBCD BinarytoDecimal:11002 =(1x )+(1x)+(0x)+(0x)2 3 2 2 2 1 2 3 =8+4+0+0=1210 DecimaltoBinary:1210 R0(LSB)12÷ 2 = 6R06 ÷ 2 = 3R13 ÷ 2 = 1R1(MSB)12÷ 2 = 61210 =11002 DecimaltoBCD:=00111000011138710 𝐵𝐶𝐷 BCDtoDecimal:010101101001 =𝐵𝐶𝐷 56910

Advantages/DisadvantagesofconvertingbetweenDecimalandBCDAdvantages:- MorestraightforwardtoconvertlargerdecimalnumbertoBCDthantoBinary- Usefulfordisplayingdecimalnumbers Disadvantages:- MorebitsareneededtostorethesamenumberinBinary BCDto7-SegmentDisplay:TodisplaybinarynumbersindecimalformInsertBCDinputinto7-segmentdecodertoconvertBCDtoa7-segmentcode BCDto7-SegmentcodeTruthTable Chapter11:BasicLogicGates LogicGatesComponentswith1ormoreinputsand1outputofeitherLogic1o