電池供電小夜燈電路

電池供電小夜燈電路
電池供電小夜燈電路--Battery-poweredNightLamp
1,R2___________1M1/4WResistorsR3_____________47K1/4WResistor(optional:seeNotes)R4____________Photoresistor(anytype,optional:seeNotes)C1____________100nF63VPolyesterCapacitorC2____________220΅F25VElectrolyticCapacitorD1______________LEDRed10mm.Ultra-bright(seeNotes)D2___________1N581940V1ASchottky-barrierDiode(seeNotes)IC1____________7555orTS555CNCMosTimerICB1_____________1.5VBattery(AAorAAAcelletc.)Devicepurpose:ThiscircuitisusableasaNightLampwhenawallmainssocketisnotavailabletoplug-inaneverrunningsmallneonlampdevice.Inordertoensureminimumbatteryconsumption,one1.5Vcellisused,andasimplevoltagedoublerdrivesapulsatingultra-brightLED:currentdrawingislessthan500΅A.AnoptionalPhotoresistorswitches-offthecircuitindaylightorwhenroomlampsilluminate,allowingfurthercurrenteconomy.Thisdevicewillrunforabout3monthscontinuouslyonanordinaryAAsizedcellorforaround6monthsonanalkalinetypecellbut,addingthePhotoresistorcircuitry,runningtimewillbedoubledor,verylikely,triplicated.Circuitoperation:IC1generatesasquarewaveatabout4Hzfrequency.C2&D2formavoltagedoubler,necessarytoraisethebatteryvoltagetoapeakvalueabletodrivetheLED.Notes:IC1mustbeaCMostype:onlythesedevicescansafelyoperateat1.5Vsupplyorless.IfyouarenotneedingPhotoresistoroperation,omitR3&R4andconnectpin4ofIC1topositivesupply.OrdinaryLEDscanbeused,butlightintensitywillbepoor.Anordinary1N4148typediodecanbeusedinsteadofthe1N5819Schottky-barriertypediode,butLEDintensitywillbereducedduetothehighervoltagedrop.AnySchottky-barriertypediodecanbeusedinplaceofthe1N5819.