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 7/13
aslongasyoukeeptheLEDwithinitssuggestedvoltageandcurrentratings.
LEDVoltage
Let’sseewhatotherkindsoftablesthey’veputinhere…Ah!
Thisisausefullittletable!ThefirstrowtellsuswhattheforwardvoltagedropacrosstheLEDwillbe.
ForwardvoltageisatermthatwillcomeupalotwhenworkingwithLEDs.Thisnumberwillhelpyou
decidehowmuchvoltageyourcircuitwillneedtosupplytotheLED.IfyouhavemorethanoneLED
connectedtoasinglepowersource,thesenumbersarereallyimportantbecausetheforwardvoltage
ofalloftheLEDsaddedtogethercan’texceedthesupplyvoltage.We’lltalkaboutthismoreindepth
laterinthedelvingdeepersectionofthistutorial.
LEDWavelength
Thesecondrowonthistabletellsusthewavelengthofthelight.Wavelengthisbasicallyavery
precisewayofexplainingwhatcolorthelightis.Theremaybesomevariationinthisnumbersothe
tablegivesusaminimumandamaximum.Inthiscaseit’s620to625nm,whichisjustatthelower
redendofthespectrum(620to750nm).Again,we’llgooverwavelengthinmoredetailinthedelving
deepersection.
LEDBrightness
Thelastrow(labeled“LuminousIntensity”)isameasureofhowbrighttheLEDcanget.Theunitmcd,
ormillicandela,isastandardunitformeasuringtheintensityofalightsource.ThisLEDhasan
maximumintensityof200mcd,whichmeansit’sjustbrightenoughtogetyourattentionbutnotquite
flashlightbright.At200mcd,thisLEDwouldmakeagoodindicator.
ViewingAngle
Next,we’vegotthisfanshapedgraphthatrepresentstheviewingangleoftheLED.Differentstylesof
LEDswillincorporatelensesandreflectorstoeitherconcentratemostofthelightinoneplaceor
spreaditaswidelyaspossible.SomeLEDsarelikefloodlightsthatpumpoutphotonsinevery
direction;Othersaresodirectionalthatyoucan’ttellthey’reonunlessyou’relookingstraightatthem.
Toreadthegraph,imaginetheLEDisstandinguprightunderneathit.The“spokes”onthegraph
representtheviewingangle.Thecircularlinesrepresenttheintensitybypercentofmaximum