electricity & electronics merit badge · types of electricity direct current (dc) type of...

6/13/17

Electricity&Electronics

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6/13/17

TypesofElectricitySta>cElectricitySta>celectricityisusuallycreatedwhenmaterialsarepulledapartorrubbedtogether,causingposi>ve(+)chargestocollectononematerialandnega>ve(−)chargesontheothersurface..Sparksmayresult!

Examplesofoccurrenceofsta>celectricity:

1.  Lightning.2.  Combinghair.3.  Walkingacrosscarpetand

geUngshocked.4.  Pullingoutscotchtape.ElectricityMeritBadgeClass1

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6/13/17 ElectricityMeritBadgeClass12017Na>onalScoutJamboree

TypesofElectricityDirectCurrent(DC)Typeofelectricityusedinmost,ifnotallelectronicswehavetoday.Currentonlyflowsinonedirec>on(notbothdirec>ons,likeAC).

ExamplesofDCusage:

1.  MP3players2.  Radios3.  Electricityincars.4.  Anywhereyouuseaba\eryfor

power.

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TypesofElectricityAlterna>ngCurrent(AC)Thecommonformofelectricityfrompowerplanttohome/office.Itsdirec>onisreversed60>mespersecondintheU.S.;50>mesinEurope.

ExamplesofACusage:

1.  Kitchens:Stoves,ovens,mixer,etc.

2.  Computerchargers3.  Lightsinhouse4.  Homeaircondi>oners.


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Voltage•  Voltsistheelectromo>veforcethatcauses electrons(current)toflow.•  Voltagecanalsobethoughtofastheelectrical

forcethatpusheselectronsinawire.•  UnitsforvoltageisVOLTS.•  ThesymbolforvoltageisE.•  Theschema>csymbolfordcvoltageisgenerallyshownasaba\ery

GND


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Voltage–WaterAnalogy

1.  Gravityprovidestheforceforwater(current)toflow.

2.  Thisillustratesasmallvoltage,socurrentflowissmall.

3.  Youcanincreasewater(current)flowbymakingthepipelargeraswell.

1.  Gravityprovidestheforceforwater(current)toflow.

2.  Thisillustratesalargervoltage,socurrentflowislarger.

3.  Youcanincreasewater(current)flowbymakingthepipelargeraswell.

Smallheight=lowvoltage Bigheight=highvoltage

height

height


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Current

•  Current:Definedas“flow(>merateofchange)ofelectrons”.

•  Current: UnitsofcurrentisAMPS.•  Current:ElectricalsymbolforcurrentisI(eye).


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CurrentFlow–WaterAnalogy

1.  Waterflowsinthehose,enteringatthetopandexi>ngthebo\om.

2.  Thewateristhe“current”;theflowofelectrons.3.  Themorewaterflowinginthepipe,themorecurrent

isflowinginthewire.4.  Differentpipediametersillustratesdifferent

resistancetowaterflow,whichcorrelatestodifferentresistorvalues.


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Resistance

•  Resistanceistheelectricalpropertyofa

substancetoresisttheflowofelectrons.•  TheunitsofresistanceisOHMS(Ω).•  ThesymbolforresistanceisR.•  Theschema>csymbolis•  Thelargertheresistance,themoreresistance

tocurrentflow.


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Resistance–WaterAnalogy

•  Differentpipediametersrepresentsdifferentresistorvalues.

•  Thesmallerthediameterofthepipe,thelargertheresistance.

1Ω

10Ω

100Ω

1000Ω

10000Ω


ElectricalTerms•  Circuit-Aconductororsystempathofelectricalelementsthroughwhichcurrentwillflow.

•  Poten>alDifference-TheVoltagebetweentwopointsinacircuit.

•  Impedance-ThetermusedinACCircuitsfortheresistancetotheflowofcurrent.

•  ShortCircuit-Anabnormalconnec>onoflowimpedance(resistance)betweentwopointsofdifferentpoten>al.

•  Ground-Apointofcommonconnec>onofzerovoltsorentheearth


OtherElectricalTerms

•  Wa\-Powertodoworkat1joule/secorW=VxI

•  Rec>fier-ElectronicorMechanicalmeanstoconvertACtoDC.

•  Rheostat-Anadjustableresistancesuchthatresistancecanbechangedwithoutbreakingthecircuit(examplelightdimmer).

•  Conductor-Materialthatwillallowcurrenttopasscon>nuouslyalongit(wire).


OtherElectricalTerms

•  Switch-ElectronicorMechanicalmeansforopeningandclosingacircuit.

•  Fuse-Adevicethatprotectsacircuitfromover-currentbymel>ngalinkinthedevice.

•  CircuitBreaker-Adevicethatprotectsacircuitforover-currentbyopeningthecircuitwithaswitch.

•  Cycle-Onecompletereversalofalterna>ngcurrentorvoltage.

•  Hertz-Onecyclepersecond


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EquipmentUsedToMeasureElectricalQuan>>esandQuali>es

Volt/Ohm/AmpMeterUsuallyreferredtoasamul>-meter.WiththiswecanmeasurecurrentA,voltageVandresistanceR.

OscilloscopeUsuallyreferredtoasaScopeorO-ScopeWiththiswecan‘see’voltagewaveforms.Thisisveryusefulwhenvoltageischanging,asameterisnogoodtouswhenthisishappening.


OhmsLawDCCircuitsVolts=CurrentxResistance

•  E=IxR •  Units– EisinVolts–  ItheelectricalcurrentisinAmps– RisResistanceisinOhmsExample:IftheVoltageEstaystheSAMEandResistanceRgoesUP,thentheamountofCurrentIflowinginthecircuitgoesDOWN


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ElectricityandElectronicSymbols

SinglePole,DoubleThrowSwitch(SPDT)

Ba\ery

Resistor

LightEmiUngDiode(LED)

Buzzer

Fuse

Lamp

or

Capacitor

Ground


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CIRCUITDIAGRAM(SCHEMATIC)

+

SWITCHLAMP10Ohms

GROUNDGROUND

FLASHLIGHT

TWOGROUNDSYMBOLSISTHESAMEASCONNECTINGWITHAWIRE

GROUND=0VOLTS

V=9V I

V=IxRV=9VoltsR=10OhmsI=?Amps9V=IAx10Ohms9V/10Ohms=IAmps0.9Amps=I

CalculateI


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ElectricitySafety•  HighVoltage(120VACorgreater)–Safetymainlyaboutnottouchingthewrongthing.

•  Currentkills–Only60voltscankillwhencurrentflowsthroughheartorheadforasufficientlengthof>me.

•  Ventricularfibrilla>on-Currentpassingthroughheartcausesknocksheartoutofsynchroniza>on.

•  Iftheshockdoesn’tkillyou,youcans>llbebadlyburnedfromtouchingthewrongthing.


ElectricShock

•  Ifapersonisincontactwithanenergized(live)circuitdonottouchthem.– Turnoffthebreaker.–  Ifyoudonotknowwherethebreakerislocatedpushthecircuitoffofthepersonwithadryobjectlikeabroom,mophandleorwoodenchair.

– Donotuseanyobjectthatismetalorwet.– Waterlikemetalcanconductelectricityinamountsthatcanbedangerous.


RemovalofLiveWire

•  Ifyoucannotremovethewirewithadryobjectorturnoffthebreakerthen:– Besureyouareonadrysurfaceand– Findadryshirt,sheetorsweaterandloopitaroundthewireandpullitoff

– Orincaseyoucannotgettothewiretrythesamemethodtopullthepersonoffthewire.

– Onceyouhaveapersonawayfromthewireschecktoseeiftheyneedar>ficialrespira>on.


HighPowerLines

•  Ifapersonisincontactwithhighpowerlines:– Donottouchthem.– Stayatleast20feetawayascurrentcanflowthroughtheground.

– Call911.– Letthefireandpolicemanagethesitua>on.

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PowerLines

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Trea>ngElectricalBurns

•  Whenapersonhasasevereelectricalburn:– Donotapplyice,ointment,water,medica>on,bandagesordressings

– Donottouchorbreakboilsorblisters– Donota\empttoremoveclothing

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ElectricalStorms•  About54peoplearekilledfromlightningeveryyearandseveralhundredareinjured.

•  Numerousforestandhousefiresarestartedbylightning.

•  Ifoutdoorsavoidtallsolitarytrees,towers,water,mountaintopsandridgecrests,metalfencesandanyobjectlikeametaltentpole.

•  Thesafestplaceisadenseforestinalowlyingarea.

•  Ifcaughtintheopenstaylow,spreadout,crouchwithbothfeettogetherandsolesontheground


ElectricalFires•  Theyaredifferentfromotherfiresinthattryingtoputoutafire:–  Neverusewater.–  Call911.–  Turnoffmainbreaker–  Useonlyex>nguishersratedforfires.ClassCfiresinvolveelectricalequipment,suchasappliances,wiring,circuitbreakersandoutlets.Neverusewater-theriskofelectricalshockisfartoogreat!TheCclassifica>onmeanstheex>nguishingagentisnon-conduc>ve.Geometricsymbol(bluecircle)

–  Iffiredoesnotgooutleavethebuilding.


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PersonalSafety•  Beawareofwhatyouaredoing,andwhereyouareplacingequipmentandyourselfinanelectricalcircuit.

•  Paya\en>ontoenergizedcircuits–Isthepoweron?Makesuretheelectricityisturnedoffespeciallywhenworkingon120VACorhigherelectricalcircuits.

•  Paya\en>ontohotsolderingirons.Keepagooddistancebetweenyouthosenexttoyou.

•  Knowwhenyouareworkingwithhighcurrentand/orhighvoltagecircuits.

•  THINKbeforeyoudosomething.•  Wearsafetyglasseswhensoldering.


6/13/17 Electricity&ElectronicsMeritBadgesClass1–2013Na>onalScoutJamboree

Howtoavoidshock.•  Turnpoweroffbeforeworkingonequipment.•  Don’ttouchcircuitsthatcouldhavehighvoltageonthem.•  Donotallowcurrenttoflowthroughheart(ormaybe

mouth,inthiscaseofanelectrifiedfence).

SampleHomeElectricalInspec>onChecklist

•  Outlets•  χCheckforoutletsthathaveloose-fiUngplugs,whichcanoverheatandleadtofire.•  χReplaceanymissingorbrokenwallplates.•  χMakesuretherearesafetycoversonallunusedoutletsthatareaccessibletochildren.•  LineCords•  χMakesurecordsareingoodcondi>on-notfrayedorcracked.•  χMakesuretheyareplacedoutoftrafficareas.•  χMakesurethatcordsarenotnailedorstapledtothewall,baseboardortoanotherobject.•  χMakesurethatcordsarenotundercarpetsorrugsoranyfurniturerestsonthem.•  ExtensionCords•  χChecktoseethatextensioncordsarenotoverloaded&onlybeusedonatemporarybasis,notaspermanentwiring.•  χMakesureextensioncordshavesafetyclosurestohelpprotectchildrenfromshockhazardsandmouthburns.•  Plugs•  χMakesureyourplugsfitsecurelyintoyouroutlets.•  χMakesurenoplugshavehadthegroundpin(thethirdprong)removedinordertomakeathree-prongfitatwo-conductor•  outlet;thiscouldleadtoanelectricalshock.•  χNeverforceaplugintoanoutletifitdoesn'tfit.•  χAvoidoverloadingoutletswithtoomanyappliances.•  GroundFaultCircuitInterrupters(GFCIs)•  GFCIscanhelppreventelectrocu>on.WhenaGFCIsensescurrentleakageinanelectricalcircuit,itassumesagroundfaulthas•  occurred.Ittheninterruptspowerfastenoughtohelppreventseriousinjuryfromelectricalshock.GFCIscanbeinstalledatthe•  outlet,orasareplacementforthecircuitbreakerforanen>recircuitatthefusebox.•  χKitchenχBathroomsχGarageχLaundryroomχOutdoors•  χTestGFCIsaccordingtothemanufacturer'sinstruc>onsmonthlyandarermajorelectricalstormstomakesuretheyare•  workingproperly.



•  LightBulbs•  χCheckthewa\ageofallbulbsinlightfixturestomakesuretheyarethecorrectwa\ageforthesizeofthefixture.•  χReplacebulbsthathavehigherwa\agethanrecommended;ifyoudon'tknowthecorrectwa\age,checkwiththe•  manufacturerofthefixture.•  χMakesurebulbsarescrewedinsecurely;loosebulbsmayoverheat.•  CircuitBreakers/Fuses•  χMakesurecircuitbreakersandfusesarethecorrectsizecurrentra>ngfortheircircuit.Ifyoudonotknowthecorrectsize,•  haveanelectricianiden>fyandlabelthesizetobeused.Alwaysreplaceafusewiththecorrectlyspecifiedsizefuse.•  χMakesureeveryoneinyourhomeknowswherethemainbreakerislocatedandhowtoshutofpowertotheen>rehouse.•  PlugInAppliances•  χMakesuretherearenoplugged-inapplianceswheretheymightfallincontactwithwater.Ifaplugged-inappliancefallsinto•  water,NEVERreachintopullitout—evenifit'sturnedoff.Firstturnoffthepowersourceatthepanelboardandthen•  unplugtheappliance.Ifyouhaveanappliancethathasgo\enwet,don'tuseitun>lithasbeencheckedbyaqualifiedrepair•  person.•  Appliances•  χIfanappliancerepeatedlyblowsafuse,tripsacircuitbreakerorifithasgivenyouashock,unplugitandhaveitrepairedor•  replaced.•  Entertainment/ComputerEquipment•  χChecktoseethattheequipmentisingoodcondi>onandworkingproperly.Lookforcracksordamageinwiring,plugsand•  connectors.•  χUseasurgeprotectorbearingthesealofana>onallyrecognizedcer>fica>onagency.


•  OutdoorSafety•  χElectric-poweredmowersandotherelectrictoolsshouldnotbeusedintherain,onwetgrassorinwetcondi>ons.•  χInspectpowertools&electriclawnmowersbeforeeachuseforfrayedpowercords,brokenplugs&crackedorbroken•  housings.Ifanypartisdamaged,stopusingitimmediately.Repairitorreplaceit.•  χAlwaysuseanextensioncordmarkedforoutdooruseandratedforthepowerneedsofyourtools.•  χRemembertounplugallportablepowertoolswhennotinuse.•  χWhenusingladders,watchoutforoverheadwiresandpowerlines.Stayatleast10feetfromalloverheadlines.•  Lightning•  χDuringanelectricalstorm,donotuseappliances(i.e.,hairdryers,toastersandradios)ortelephones(exceptinan•  emergency);donottakeabathorshower;•  χKeepba\eriesonhandforflashlightsandradiosincaseofapoweroutage.•  χUsesurgeprotectorsonelectronicdevices,appliances,phones,faxmachinesandmodems.•  SpaceHeaters•  χSpaceheatersaremeanttosupplysupplementalheat.Keepspaceheatersatleast3r.awayfromanycombus>ble•  materialssuchasbedding,clothing,draperies,furnitureandrugs.•  χDon'tusespaceheatersinroomswherechildrenareunsupervisedandremembertoturnoffandunplugwhennotinuse.•  χDonotusespaceheaterswithextensioncords;plugdirectlyintoanoutletonarela>velyunburdenedcircuit.•  HalogenFloorLamps•  χHalogenfloorlampsoperateatmuchhighertemperaturesthanastandardincandescentlightbulb.Neverplaceahalogen•  floorlampwhereitcouldcomeincontactwithdraperies,clothingorothercombus>blematerials.•  χBesuretoturnthelampoffwheneveryouleavetheroomforanextendedperiodof>me.•  χNeverusetorchierelampsinchildren'sbedroomsorplayrooms.Considerusingcoolerfluorescentfloorlamps.



Howcanwesaveenergyinourhomes,schoolsandscoutareas

•  Turnoffunneededorunusedlights•  Unplugchargerswhennotinusecharging•  Whenappliancesneedtobereplacedbuyenergystarappliances

•  Inthesummersettheindoortemperatureadegreeortwohigherandinwinteradegreeortwolower

•  TurnofftheTVwhenleavingtheroom6/13/17 ElectricityMeritBadgeClass1

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•  Plantripstothestoresothatonetripcancompleteseveralerrands

•  Don’texceedthespeedlimit•  Useabikeforshorttripsratherthanacar•  Makesurethatthebuildinghasadequateinsula>on

•  Stopallairleaksinabuildinguseinfraredscannertofindleaks



•  Cleanorreplaceairfiltersregularly•  Useenergyefficientlightbulbs•  Keepthedoorsclosedwhencoolingorhea>ng•  Shadeyourwindowsinthesummer•  Useceilingfans•  Closeallfireplaceflueswhennotinuse•  Washonlyfullloads•  Setwashersoneconomyloadtosavewater



•  Setwatertemperaturelower•  Takeshortershowers•  Don’tletthewaterrunwhilebrushingorshaving

•  LookforenergyefficientcomputersandTVs•  Unplugunusedappliancesanddevicesastheyusepoweratall>mes


electricity & electronics merit badge · types of electricity direct current (dc) type of...

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