Bill, It looks like they have a forward voltage of 2.0 volts for red, and 2.1 volts for green. In other words, that's how much voltage you will lose across the LED. For more info, see
http://www.kpsec.freeuk.com/components/led.htm This number is important for calculating the resistor needed, and for how many LEDs you might be able to connect to one power supply before you run out of juice. You calculate the resistor needed by taking your supply voltage, minus the LED forward voltage, and divide the resulting voltage by the recommended amps, 0.020A in this case. If you use less resistance, the LED will burn brighter and die sooner. If you use more resistance, the LED will be less bright, but it will last "forever". So, if you have a 9V battery, you would have, (Vs - Vf)/I = (9 - 2.0)/0.020 = 7/0.02 = 350 ohms. You then need to calculate the wattage across the resistor. P = V * I = 2.0 * 0.02 = 0.04W. A 1/8 (0.125) watt resistor (the smaller ones) would be sufficient for this application. Look for the next higher standard ohms value resistor at your favorite electronics stores (or your parts bin). From the spec sheet diagram, the center pole (the longer one) is the negative. The outer legs are the positives. Current needs to flow from outer leg to center leg to get the appropriate color to light up. Feed the output of your switch machine to the outer legs, and have the common ground connected to the center leg. You can put one resistor on the negative leg, OR one on each outer leg. Whether this LED works for your particular switch machine set-up is up to you to determine. Looks like a good deal for 40 of 'em. - Peter. On 03/31/2011 1:19 pm, Bill Lane wrote: > Electronic gurus! > > > > I just found what looks like a killer deal on some bicolor LEDs like I have > previously discussed. Please see eBay item 120611312978 > > > > You can just put the item number is any search and it will take you there. > About ½ way down the page is a technical page link. I tried to read it and > got lost. > > > > What is the operating voltage range for these? Am I correct that the center > lead is 1 pole that the outer leads would flop the colors? I would much > prefer to just go hot with the 6-12 volt switch motor system I am making, > and not have to resistor down every LED. If this is LED cannot run on 6-12 > volts does this seller have a green-red 5MM LED that can? > > > > > > > > Thank You, > Bill Lane > > Modeling the Mighty Pennsy& PRSL in 1957 in S Scale since 1988 > > See my finished models at: > <http://www.lanestrains.com/> http://www.lanestrains.com > Look at what has been made in PRR in S Scale! > > Custom Train Parts Design > <http://www.lanestrains.com/SolidWorks_Modeling.htm> > http://www.lanestrains.com/SolidWorks_Modeling.htm > > PRR Builders Photos Bought, Sold& Traded > (Trading is MUCH preferred) > <http://www.lanestrains.com/PRRphotos.xls> > http://www.lanestrains.com/PRRphotos.xls > > ***Join the PRR T&HS*** > The other members are not ALL like me! > <http://www.prrths.com/> http://www.prrths.com > <http://www.lanestrains.com/PRRTHS_Application.pdf> > http://www.lanestrains.com/PRRTHS_Application.pdf > > Join the Pennsylvania Reading Seashore Lines Historical Society > It's FREE to join!<http://www.prslhs.com/> http://www.prslhs.com > Preserving The Memory Of The PRSL > > > > > > [Non-text portions of this message have been removed] > > > > ------------------------------------ > > Yahoo! Groups Links > > > > -- Peter Vanvliet ([email protected], or [email protected]) Houston, Texas "It is easy to give up; anyone can do that..." http://pmrr.org/ (my model railroad - RSS feed <http://pmrr.org/rss.xml>) http://fourthray.com/ (my company) http://houstonsgaugers.org/ (model railroad club) -- [Non-text portions of this message have been removed] ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/S-Scale/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/S-Scale/join (Yahoo! ID required) <*> To change settings via email: [email protected] [email protected] <*> To unsubscribe from this group, send an email to: [email protected] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
