Data Sheet

6/30/2015 LightemittingDiodes(LEDs)learn.sparkfun.com
https://learn.sparkfun.com/tutorials/lightemittingdiodesleds?_ga=1.43468261.1900427809.1434378181 10/13
HighPowerLEDs,frommanufacturerslikeLuxeonandCREE,arecrazybright.Generally,anLEDis
consideredHighPowerifitcandissipate1Wattormoreofpower.ThesearethefancyLEDsthatyou
findinreallyniceflashlights.Arraysofthemcanevenbebuiltforspotlightsandautomobileheadlights.
Becausethere’ssomuchpowerbeingpumpedthroughtheLED,theseoftenrequireheatsinks.A
heatsinkisbasicallyachunkofheatconductingmetalwithlotsofsurfaceareawhosejobistotransfer
asmuchwasteheatintothesurroundingairaspossible.HighPowerLEDscangeneratesomuch
wasteheatthatthey’lldamagethemselveswithoutpropercooling.Don’tlettheterm“wasteheat”fool
you,though,thesedevicesarestillincrediblyefficientcomparedtoconventionalbulbs.
ThereareevenLEDsthatemitlightoutsideofthenormalvisiblespectrum.YouprobablyuseInfrared
LEDseveryday,forinstance.They’reusedinthingslikeTVremotestosendsmallpiecesof
informationintheformofinvisiblelight!Ontheoppositeendofthespectrumyoucanalsoget
UltravioletLEDs.UltravioletLEDswillmakecertainmaterialsfluoresce,justlikeablacklight!They’re
alsousedfordisinfectingsurfaces,becausemanybacteriaaresensitivetoUVradiation.
WithfancyLEDsliketheseatyourdisposal,there’snoexcuseforleavinganythingunilluminated.
However,ifyourthirstforLEDknowledgehasn’tbeenslaked,thenreadon,andwe’llgetintothe
nittygrittyonLEDs,color,andluminousintensity!
DelvingDeeper
Soyou’vegraduatedfromLEDs101andyouwantmore?Oh,don’tworry,we’vegotmore.Let’sstart
withthesciencebehindwhatmakesLEDstick…err…blink.We’vealreadymentionedthatLEDsarea
specialkindofdiode,butlet’sdelvealittledeeperintoexactlywhatthatmeans:
WhatwecallanLEDisreallytheLEDandthepackagingtogether,buttheLEDitselfisactuallytiny!
It’sachipofsemiconductormaterialthat’sdopedwithimpuritieswhichcreatesaboundaryforcharge
carriers.Whencurrentflowsintothesemiconductor,itjumpsfromonesideofthisboundarytothe