Electronics How bright are these?

How bright in terms of LED MCD would these be, like 3000mcd, I dont get the "Lumens"?. Im interested in the Star/O version. Thanks

http://www.luxeonstar.com/luxeon-star.html

Also can I run this off a 12v or does it need a 5v?....if so what else would I need to run it. Thanks guys I have no electrical skills. And if some1 could explane the difference between the "Batwing" and "Lambertian"....thanks again

 

got this from http://www.superbrightleds.com/led_info.htm
hope it helps

 

Ok linear I just read ur review of them and damn are they bright. So for a complete noob like me can you explane in 3yr old talk what resistor I would need to run this off a 5v. Im going to buy the Red and Blue for starters. Iv read over the calculator info but its useless, I dont understand. Thanks


http://www.bit-tech.net/review/82/

 

any1?

 

1000 mcd (millicandela) is the same as 1 cd (candela). That means that an LED with a value of 3000mcd is equally bright to three wax candles burning simultaneously. Note that the light beam of an LED is much more focused, so it appears brighter. You will hurt your eyes if you look directly into the 3000mcd LED for a short period.

 

sorry this is what I need to know now.....what resistor I would need to run this off a 5v?

 

Moving to Electronics.

*n

 

Mudslag, just tell me the current and voltage of the LED, and I'll tell you the resistor value you need.

 

this is the one I got....http://www.bit-tech.net/review/82.....but the resistor I got was a 33 Ohm 1/2watt not the 1/4watt....Ratshack didnt have the 1/4.


Will this worK?

 

yep a 1/2 will work just as goot as a 1/4.

 

thanks guys for all the help.....2 more ?s (4 now ).......Is there any way to bring the number of resistors down to 1 resistor, if so what resistor would I need? and the really stupid question, The resistors connect to the 5v or the ground?....thanks again.

 

what?? you only need one 3.3 6.8 ohm resistor(not 33ohm) if your using one light or a higher value if you want to play it safe, and it can be on either side of the led. (actualy you should use a 1/2W instead of a 1/4W)

 

The wattage of teh resistor just tells you how much energy the resistor can dissipate, obviously a 1/2W will dissipate more than a 1/4 W

linear has a led calculator on his site that will handle the star/o's

 

linear said he used 5 33ohm resistors in the artical.....did I read it wrong?

 

Yes he said that, but he ment in parallell.
Rtot= 1/(1/33+1/33+1/33+1/33+1/33) = 6,6ohm

If you want to use it from a 12v supply
R= (Vs-Vf)/If = (12v-2,95)/0,35= 25,8 ohm

But if you are going to use one resistor it have to have a wattage larger then 3,2W for 12v supply and larger then 0,8W for 5v supply

P12V = (Vs-Vf)*If=(12V-2,95V)*0,35= 3,17W

P5V = (Vs-Vf)*If=(5V-2,95V)*0,35= 0,72W

 

Thanks guys....Ill do the 3.3 1/2watt for the 5v......then what one is needed for a 12v....and I take it would be much brighter with a 12v over the 5v right?


Im sorry but when I see this, my brain turns to jello

P12V = (Vs-Vf)*If=(12V-2,95V)*0,35= 3,17W

P5V = (Vs-Vf)*If=(5V-2,95V)*0,35= 0,72W

 

I Too am curious about the difftence between batwing and lambertian

Anybody got a clue?

 

-How can you go for the 3.3ohm? It's to small and will just fry your'e led. If you read the article, linear have calculated that you need a 5.85ohm resistor. And the wattage is to small

-Read my post above

-It would be just as bright at 5v supply as if you use 12v supply. the only difference is that you have to use a larger resistor at 12v supply to get the right Vf (volt forward= volts over the led)

 

ConKbot of Doom said 3.3 thats why I got a 3.3.....now im all confused....so for a 5v line get a 5.85?

 

hmm, the other day when I put it in the BT led calculator, for some reason it spit out 3.3 ohms, but now its saying 6.8 ohms. I think I put 3.95 in for Vf instead of 2.95. So it is 6.8 ohms, not 3.3.