TheBackShed.com

Forum Index : Electronics : Types of LEDs

Author

Message

mahela007

Newbie

Joined: 06/07/2008
Location: Sri Lanka
Posts: 29

Posted: 12:13pm 25 Aug 2008

Copy link to clipboard

Print this post

I was hunting for LEDs to power my windmill when I ran into two different types of LEDs. Just out of pure curiosity I bought both and tested them at home. One is a standard LED and is like all the other LEDs that I have seen upto now. The second one however is way different. It is the same hight as the other one but is slighly thinner. when you look at it from the top it looks like an oval rather than a circle. In addition to that it seems to be atleast 5 times more powerful than the normal LED. Infact the flash of light it gives is almost blinding. Have you ever looked at the sun and then noticed temporary purple patches in your vision? (Maybe not because you would have to be as stupid as me to do that) Well I get patches like that when I look at this LED as well. Does anyone know about this kind of LED? Are they special or just high power versions of the normal ones?

They dont seem to draw a vastly different amount of power to give out the light but they deffinitely do take a little more voltage. (unfortumately I dont have any specific numbers)

I forgot to mention it is Blue in color.Edited by mahela007 2008-08-26

how come its not very windy where i live???

Dinges
Senior Member

Joined: 04/01/2008
Location: Albania
Posts: 510

Posted: 02:42pm 25 Aug 2008

Copy link to clipboard

Print this post

Quote from this thread (
http://www.thebackshed.com/windmill/FORUM1/forum_posts.asp?T ID=1199&PN=1):

dinges said 135.000 mCd. Yikes. I played with a few 25.000 mCd LEDs in the distant past. The datasheet warned not to look into the beam. 'yeah, right', dinges said, as he pointed the bright red LED towards his eyes. [Expletives deleted] bright they were. For minutes I had a negative image (blue spot) on my retina, wherever I looked. Now, 135.000 mCd...

This happened about 10 years ago, by now there surely exist much brighter LEDs. BTW, note that part of this brightness is caused by focusing it into a very narrow beam: it is bright when you look straight into the beam, but very dim when you're just outside the main beam. It's the difference between 'candela' and 'lumen'. Wikipedia can explain the difference better than I.

Quote Have you ever looked at the sun and then noticed temporary purple patches in your vision?

In my case it turned out to be more of a permanent patch in my left eye (actually, a 'blob' with a streak attached with a few sharp bends into it; the blob moves wherever my eyes move to). I prefer to think I'm in the good company of Galileo rather than being stupid...

Edited by Dinges 2008-08-27

mahela007

Newbie

Joined: 06/07/2008
Location: Sri Lanka
Posts: 29

Posted: 03:13pm 25 Aug 2008

Copy link to clipboard

Print this post

Dinges said
135.000 mCd. Yikes. I played with a few 25.000 mCd LEDs in the distant past. The datasheet warned not to look into the beam. 'yeah, right', dinges said, as he pointed the bright red LED towards his eyes. [Expletives deleted] bright they were. For minutes I had a negative image (blue spot) on my retina, wherever I looked. Now, 135.000 mCd...

i dont think the LED I am reffering to is as powerful as that. I will try to post some pictures

how come its not very windy where i live???

Print this page

To reply to this topic, you need to log in.