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 6/13
Ofcourse,ifyou’renotgettinggreatresultswiththetrialanderrorapproach,youcanalwaysgetout
yourcalculatorandmathitup.Don’tworry,it’snothardtocalculatethebestresistorvalueforyour
circuit.Butbeforeyoucanfigureouttheoptimalresistorvalue,you’llneedtofindtheoptimalcurrent
foryourLED.Forthatwe’llneedtoreporttothedatasheet…
GettheDetails
Don’tgoplugginganystrangeLEDsintoyourcircuits,that’sjustnothealthy.Gettoknowthemfirst.
Andhowbetterthantoreadthedatasheet.
Asanexamplewe’llperusethedatasheetforourBasicRed5mmLED.
LEDCurrent
Startingatthetopandmakingourwaydown,thefirstthingweencounteristhischarmingtable:
Ah,yes,butwhatdoesitallmean?
ThefirstrowinthetableindicateshowmuchcurrentyourLEDwillbeabletohandlecontinuously.In
thiscase,youcangiveit20mAorless,anditwillshineitsbrightestat20mA.Thesecondrowtellsus
whatthemaximumpeakcurrentshouldbeforshortbursts.ThisLEDcanhandleshortbumpsto
30mA,butyoudon’twanttosustainthatcurrentfortoolong.Thisdatasheetisevenhelpfulenoughto
suggestastablecurrentrange(inthethirdrowfromthetop)of1618mA.That’sagoodtarget
numbertohelpyoumaketheresistorcalculationswetalkedabout.
Thefollowingfewrowsareoflessimportanceforthepurposesofthistutorial.Thereversevoltageis
adiodepropertythatyoushouldn’thavetoworryaboutinmostcases.Thepowerdissipationisthe
amountofpowerinmilliWattsthattheLEDcanusebeforetakingdamage.Thisshouldworkitselfout