Electronics notes (Analogue)

Electronicsnotes(Analogue)(pmsomething3009ondiscordifthereareanyerrors)Chapter Content Examples Chapter1:ElectronicSystems Mainpartsofelectronicsystems:InputSubsystem,ProcessSubsystem,OutputSubsystem Calculators, Microphones,hairdryer,ect BlockDiagram(egthermometer) Howelectronicsystemsarepresented:BlockDiagrams(seeabove):ProvidesoverviewofsystemCircuitDiagram:Givesinformationonhowthecircuitisbuilt,andcontainsvalues,componentsandthewayitisconnected CircuitDiagram: Howdoesinformationflowinelectronicsystems?Electronicsystemscanonlyprocessinfointheformofelectricsignals(voltage/currentsthatcarryinfo)nonelectricalinfo(input)->Electricalinfo(process)->nonelectricinfo(output) Analoguesignals:0to5VDigitalsignals:0OR5V Chapter2:CurrentElectricity Voltage:Comesin2formsElectromotiveforce(EMF):TotalvoltageofbatteriesconnectedinseriesorparallelEffectiveEMFinseries=𝐸1 +𝐸2 +𝐸3 + ...+𝐸𝑛 EffectiveEMFinparallel=samewithallotherbatteriesinparallel(usuallyofsamevoltage)PotentialDifference(P.D.):Workdonetodriveaunitchargethroughacomponentorinbetween2pointsinacircuit

CurrentRateofflowofElectricChargeConventionalcurrentflow:Frompositivetonegativeterminal(mostlyused)Electronflow:Fromnegativetopositiveterminal𝐼 = 𝑄𝑡I-Current(A)Q-Charge(Columb)(C)t-Timeinseconds(s) *Currentrating:Maximumcurrentaconductorcancarrywithoutoverheatingorbeingdamaged ResistanceAmeasureofhowdifficultitisforacurrenttoflowthroughacomponent𝑅 = 𝑉𝐼R-Resistance(Ohm)(Ω)V-Voltageacrosscomponent(V)I-Current(A) Ohm’slawCurrentinametallicconductorisdirectlyproportionaltoP.D.acrossconductor(LinearI-Vgraph,startfromorigin) Non-ohmicconductorsarenotlinearornotstartingfromtheorigin Ohmicconductors:Resistor Non-Ohmicconductors:FilamentBulb,SemiconductorDiode HeatingeffectofCurrentHeatisproducedwhencurrentflowsthroughacomponentHeatisbadasitcancauseelectroniccomponentstooverheatandbedamaged,energyisalsowasted Power:RateofEnergyconversionor𝑃 = 𝐼𝑉 𝑃 = 𝐸𝑡

Formulacanberearrangedto 𝑃 =𝐼 2 𝑅 or𝑃 = 𝑉 2 𝑅V-Voltageacrosscomponent(V)I-Current(A)R-Resistance(Ohm)(Ω)E-Amountofenergyconverted(J)t-Timeinseconds(s) Powerrating:Maximumpoweratwhichacomponentcanbeusedwithoutbeingdamaged*Pickpowerratingof2xthecalculatedvalue Ifpowerdissipatedis0.20W,pickresistorwith0.5Wpowerrating Energy𝐸 = 𝑉𝐼𝑡E-Amountofenergyconverted(J)V-Voltageacrosscomponent(V)I-Current(A)t-Timeinseconds(s) Energyefficency:ThepercentageofinputenergythatisconvertedtousefulenergyEfficiency=usefulpoweroutput/powerinputx100% Chapter3:Resistors Resistanceofaconductorisaffectedby4factors- Resistivityofmaterial- Lengthofconductor(Longerlength,higherresistance)- Cross-Sectionalareaofconductor(Largercross-sectionalarea,lesserresistance)- TemperatureFormula:𝑅 = ρ𝑙𝐴R-Resistance(Ohm)(Ω)P-Resistivityofmaterial(Ω m)l-Lengthofmaterial(m)A-Crosssectionalarea(m²)

Typesofresistors:Fixedresistors,Variableresistors Fixedresistors:Carbon,Wire-woundDifferences:Carbon Wire-wound Lowpowerapplications High-powerapplications Lowtemperaturestability Hightemperaturestability Typicalpowerratingrangeof0.1W-2W Typicalpowerratingrangeof2W-500W Lowcost Highcost Variableresistors:Trimpot,Potentiometer.ect Howtodeterminevalueofresistor:ResistorColourCode:Seriesof4colouredbandsonCarbonresistorFromlefttoright:1stand2ndband:Number3rdband:Multiplier(no.of0)4thband:Percentagetolerance(eg±5%) E24series:Calculatevalueneeded,thenchooseavalueclosesttothecalculatedvaluefromtheE24series*SelectionofResistors:-Fornon-BJTs,pickvaluemorethancalculatedone(reducecurrenttopreventoverloading/damage)-ForBJTs,pickvaluelessthancalculatedone(increasecurrentflowingthroughtransistorbeforeBJT,makeIBlargeenoughtopushBJTtosaturation) Resistorwithbandcoloursyellowpurpleorangegold:47㏀±5% Ifa124Ωresistorvalueiscalculated,usea130ΩresistorfromE24series

Resistorsinseries/parallel Inseries:𝑅𝑒𝑓𝑓 =𝑅1 +𝑅2 + ...+𝑅𝑛 Inparallel:1𝑅𝑒𝑓𝑓 = 1𝑅1 + 1𝑅2 + ...+ 1𝑅𝑛 Powerrating(Resistors)Iftemperatureishighenough,cancauseresistortooverheat(damageresistor) Resistorwithpowerratingof0,25Wcanonlywithstand0.25WItisgoodpracticetopickpowerrating2xofcalculatedvalue(eg0.5W) Chapter4:CircuitTheories Commontermsusedtodescribeacircuit:Circuits-Consistsofelectricalcomponentsconnectedtogetherwithwires,providesoneormorepathsforcurrenttoflow Source-Itprovidesthee.m.f.neededtomoveelectricchargesaroundthecircuit. Load-Acomponentwhichconvertselectricalenergysuppliedbyasourceintootherforms Open/Closedcircuit-Acircuitwithout/withacontinuouspathlinkingthepositiveterminaltothenegativeterminalofasource. ShortCircuit--Alow-resistancepaththatisusuallyundesirableandharmful. Overloading-occurswhencurrentexceedscurrentrating

Voltageandcurrentinseriesandparallel Voltage/Currentinseries:𝑉 =𝑉1 +𝑉2 +𝑉3 𝐼 =𝐼1 =𝐼2 Voltage/Currentinparallel:𝑉 =𝑉1 =𝑉2 =𝑉3 𝐼 =𝐼1 +𝐼2 +𝐼3 Voltage/CurrentDivider VoltageDivider: 𝑉1 = 𝑅1 𝑅1 +𝑅2 × 𝐸 CurrentDivider: 𝐼2 = 𝑅2 𝑅1 +𝑅2 × 𝐼 KirchhoffCurrent/VoltageLaw KCL:Sumofallcurrententeringandleavinganode=0,currentthatenterthenodeispositive,currentthatleavesthenodeisnegative 𝐼1 +𝐼4 =𝐼2 +𝐼3 0 =𝐼1 +𝐼4 −𝐼2 −𝐼3

KVL:Sumofallvoltagesinclosedloop=0,voltageincreaseinloopdirectionispositive,voltagedecreaseinloopdirectionisnegative*WhennoV,useIRassubstitute 𝐸 =𝑉1 +𝑉2 +𝑉3 0 = 𝐸 −𝑉1 −𝑉2 −𝑉3 Chapter5:AlternatingCurrents DirectCurrent(DC):Currentflowsin1direction,terminalsdonotchangepolarity AlternatingCurrent(AC):Currentchangesdirectionsperiodically(Terminalschangepolarity) DC:Batteries AC:ACGenerators TypesofACWaveforms Periodic:Sinusoidal,Rectangular,Square,Triangular Non-Periodic:Waveformsthatdonotrepeatthemselves(egmicrophonesignals) WaveformsaregeneratedbyFunctionGenerator,waveformscanbeobservedviaOscilloscope Periodicwaveforms DescribingACwaveforms DCLevel:Voltagelevelwhichwaveformoscillatesabout Peakvoltage( ):HighestpointfromDC𝑉𝑃 level Peak-to-Peakvoltage( ):Lowestto𝑉𝑃𝑃 highestpoint

Dutycycle:Percentageofrectangularwaveformwhenwaveformisathigherlevel Period:Timetakentocomplete1cycleofwaveform Frequency:NumberofcompletecyclescreatedeverysecondFormula:𝑓 = 1𝑇f-Frequency(Hz)T-Period(s) DutycycleisthepercentageoftheperiodofarectangularwaveformwhenitisatthehighervoltagelevelPowersuppliedtoadevicecanbecontrolledbyadjustingDutycycle Dutycycle= 𝑡ℎ𝑖𝑔ℎ 𝑇 × 100% Chapter6:Capacitors Capacitorsconsistsof2metalplatesseparatedbyaDielectric Dielectric:insulatingmaterialseparatingtwometalplates Charging:Safetyprecautions:connectaresistorbetweenthe2metalplatestodischarge.Itcannotbedischargeddirectlyasitwillcausealargecurrentspikewhichwilldamagethecapacitor UsesofCapacitors:Voltage-Smoothing(Full-waverectifier),CouplingCapacitors(BJTamplifier) DetermininghowmuchchargeaCapacitorcanstore 𝐶 = 𝑄𝑉C-Capacitance(F)Q-Chargestored(Columb)(C)V-Voltage(V)

Factorsaffectingcapacitance:- Areaofmetalplates(larger=morecapacitance)- Distanceseparatingplates(longer,lesscapacitance)- MaterialusedforDielectric TypesofCapacitors:Polarised,Non-polarised Electrolytic(Polarised):Shortleg(-ve),-vesignside,valuesoncapacitor Ceramic(pF)(Non-polarised):NopolarityToidentifyvalue:first2digitsinpF,thirddigitmultiplier(noofzerosafterthe2digits) Difference:Polarised Non-polarised Havelargecapacitances Havesmallcapacitances Havefixedpositiveandnegativeterminals Nofixedpositiveornegativeterminals Typicallylargerinsize Typicallysmallerinsize E24series:Calculatevalueneeded,thenchooseavalueclosesttothecalculatedvaluefromtheE24series(Similartoresistors) Maximumworkingvoltage:Voltageappliedoncapacitormustnotexceedorcapacitormaybedamaged 472is4700pF Ifa467nFcapacitorvalueiscalculated,usea470nFcapacitorfromE24series Capacitorsinseries/parallel Inseries:1𝐶𝑒𝑓𝑓 = 1𝐶1 + 1𝐶2 + ...+ 1𝐶𝑛

Inparallel:𝐶𝑒𝑓𝑓 =𝐶1 +𝐶2 + ...+𝐶𝑛 RCCircuitsτ = 𝑅𝐶𝜏-Timeconstantinseconds(s)R-Resistance(Ω)C-Capacitance(F) Resistoraffectscharging/dischargingtimeofacapacitorDeterminescharging/dischargingtimeofcapacitor Charging/discharging:Time Charging Discharging 𝜏 23 𝑉𝑐𝑐 13 𝑉𝑐𝑐 5 𝜏 Fullycharged Fullydischarged Charginggraph: Discharginggraph: Chapter7:SemiconductorDiodes StructureofaDiode TypesofSemiconductorsafterDoping:N-type,P-typeN-type:rely