最重要的发明 -- 电灯.ppt

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1、Themostimportantinvention----LightIntroductionTheFirstElectricLightMadein1809byHunphryDavy,thisiscalledtheelectricarc.LateTheAmericanCharlesFranciesBrushmanufacturedsomecarbonarcs.TheInventorThomasEdisonexperimentedwiththousandsofdifferentmaterials,event

2、uallyproducedabulbthatcouldglowforover1500hours.汉弗莱·戴维爵士（法拉第的老师）[ɑːk]电弧manufactured[,mænjə'fæktʃɚ]制造，加工（manufacture的过去式）carbonarcs[电]碳弧bulb[bʌlb]电灯泡Therearethreekindsoflight.1.Incandescentlamp(白炽灯)：a.Incandescentlamp（白炽灯）b.Tungstenhalogenlamp（卤钨灯）c.Halog

3、enlamp（卤素灯）......2.Highintensitydischargelamp-HID（气体放电灯）a.Fluorescentlamp（荧光灯）b.Sodiumlamp（钠灯）c.Metalhalidelamp（金属卤化物灯）......3.Others.a.ElectrodelessLamp（高频无极灯）b.LightEmittingDiode（发光二极管）......Intheearly19thcentury，aBritishchemistmadethefirstarclampinthe

4、worldbyusing2000cells(电池）and2carbonrods.Butthiskindoflightistoostrong，itcannotbeusedinthehousebutonlyinthestreet.In1879ByThomasEdison--anAmericaninventorThetemperatureofthefilament:3000℃Averagelifespan:1000hIt'salampwhichranksfirstintheproductionofthewor

5、ld.Butmanycountriesaretryingtostopusingit,becauseofitsheavypollution.Incandescentlamp（白炽灯）filament['fɪləmənt]灯丝lifespan寿命ComparetoIncandescentlamp,thiskindoflamphaslongerlifespan(4000h)andhigherlightefficiency.ItItisoftenusedinthemeetingroom,theexhibitio

6、nhallandthestage.TungstenHalogenLamp（卤钨灯）lightefficiency光效率FluorescentLamp（荧光灯，俗称日光灯）Longlifespan:2500h~3500hHighlightefficiencyGoodcolorrenderingThetemperatureofthefilament:≤1000℃colorrendering显色性SodiumLamp(钠灯)Thehighestlightefficiency.FogpermeabilityLi

7、fespan:20000hBeusedinroads,airports,terminals,highways,etc.Fogpermeability透雾性ElectrodelessLamp（高频无极灯）Verylonglifespan:40000h~80000hEnergysavingBrighterSo,itisoftenusedinsomeplaceswhichhavehigherrequirementsforsafety.Suchastunnels,subwaystationsandfactori

8、es.tunnels隧道LightEmittingDiode（发光二极管）Samefeaturesaselectrodelesslamp,butmoreenergysaving.Itissecurewhenitworkunderthelowthermalvoltage.Andit'ssurfacetemperaturelessthan60℃.lowthermalvoltage低热电压Whatwillhappenifourworldhaven