衰落髮光二極體電路

衰落髮光二極體電路
衰落髮光二極體電路--FadingLEDsTwostripsofLEDsfadinginacomplementarymanner9VBattery-operatedportableunit
Parts:R1,R2_______________4K71/4WResistorsR3_________________22K1/4WResistorR4__________________1M1/4WResistor(SeeNotes)R5__________________2M21/4WCarbonTrimmer(SeeNotes)R6,R10,R11,R14,R15_10K1/4WResistorsR7,R8______________47K1/4WCarbonTrimmers(SeeNotes)R9,R13_____________27K1/4WResistorsR12,R16____________56R1/4WResistorsC1__________________1΅F63VPolyesterCapacitorC2________________100΅F25VElectrolyticCapacitorD1-D4etc._________5or3mm.LEDs(anytypeandcolor)(SeeNotes)IC1_______________LM358LowPowerDualOp-ampQ1,Q2,Q4__________BC32745V800mAPNPTransistorsQ3,Q5,Q6__________BC33745V800mANPNTransistorsSW1________________SPSTminiatureSliderSwitchB1___________________9VPP3BatteryClipforPP3BatteryDevicepurpose:ThiscircuitoperatestwoLEDstripsinpulsingmode,i.e.oneLEDstripgoesfromoffstate,lightsupgradually,thendimsgradually,etc.whiletheotherLEDstripdothecontrary.Eachstripcanbemadeupfrom2to5LEDsat9Vsupply.Circuitoperation:ThetwoOp-AmpscontainedintoIC1formatriangularwavegenerator.Therisingandfallingvoltageobtainedatpin#7ofIC1drivestwocomplementarycircuitsformedbya10mAconstantcurrentsource(Q1,Q2andQ5,Q6)anddrivertransistor(Q3andQ6).R4,R5&C1arethetimingcomponents:thetotalperiodcanbevariedchangingtheirvalues.R7&R8varytheLEDsbrightness.Notes:Forthosewhishingtoavoidtheuseoftrimmers,suggestedvaluesfora9Vsupplyare:R4=3M9,R9&R13=47Kandtrimmersreplacedbyashort.Whishingtouseawall-plugtransformer-supplyinsteadofa9Vbattery,youcansupplythecircuitat12V,allowingtheuseofupto6LEDsperstrip,orat15V,allowingtheuseofupto7LEDsperstrip.Inthiscase,thevalueofthetrimmersR7&R8shouldbechangedto100K.