[Boards: 3 / a / aco / adv / an / asp / b / biz / c / cgl / ck / cm / co / d / diy / e / fa / fit / g / gd / gif / h / hc / his / hm / hr / i / ic / int / jp / k / lgbt / lit / m / mlp / mu / n / news / o / out / p / po / pol / qa / r / r9k / s / s4s / sci / soc / sp / t / tg / toy / trash / trv / tv / u / v / vg / vp / vr / w / wg / wsg / wsr / x / y ] [Home]
4chanarchives logo
How much power does a led emitting 6000 mcd of 465 nm blu light
Images are sometimes not shown due to bandwidth/network limitations. Refreshing the page usually helps.

You are currently reading a thread in /sci/ - Science & Math

Thread replies: 18
Thread images: 2
File: piceds.jpg (659 KB, 2197x1463) Image search: [Google]
piceds.jpg
659 KB, 2197x1463
How much power does a led emitting 6000 mcd of 465 nm blu light in a 20 degrees angle converts into luminous energy (Watts)? All the light the led emits is captured, so I don't care how wide the beam is, just how many watts I can gather.
I tried searching for led efficiency but all I find is lumen/watt. The problem is that it is calculated for 550 nm light, and I don't know how to calculate that for blue light. Any ideas?
>>
Anyone has some advice?
>>
Just give me an advice
>>
Please
>>
https://en.wikipedia.org/wiki/Candela#Explanation
<--wavelength dependent formula
>>
>>7809043
According to my math, one of these leds https://www.adafruit.com/products/301 outputs only 0.01 W. Is this even possible?
>>
>>7809811
yes, most commong 5mm leds are 0,01W/0,25W/0,6W/1W
>>
>>7809818
Are you talking about the power they use or about the power they output?
>>
>>7809825
if you tried to integrate the emitted wavelengths to find out the power it emits 0,01 sounds like a reasonable result.
>>
>>7809867
just write down or screencap what you're trying to find out and i'll help. also post a pic of your calculations
>>
>>7807680
>I don't know how to calculate that for blue light.
It's not a calculation; light follows aberrant quantity rules. Detection depends on the composition of the measuring body, wattage inclusive.
>>
>>7809887
I'll explain everything:
According to this paper ( http://emedicine.medscape.com/article/1894477-overview#a4 ) I need 10 mW/cm^2 of blue light at 458 nm (I found those 465 nm blue led: https://www.adafruit.com/products/301 ), over an area of 0.10 m^2 (30 * 30 cm).
Now I can't tell how many leds would I need to get those 10 W.
If every single of those leds output 0.01 W I'd need 1000 of them, but that seems overkill.
Anyway this is how I calculated it:
6 cd / (683 * 0.1).
I got the last number from this site ( http://www.cvrl.org/lumindex.htm ) for 465 nm light.
That gives me 0.1 W/sr.
In the leds vendor page the viewing angle is listed to be 20 degrees (10 + 10).
So it covers a solid angle of (assuming a sphere of radius 1): PI * (sin 10°)^2 / (1^2), which is 0.1 sr.
It follows that the total power that a single led emits is 0.1 W/sr * 0.1 sr = 0.01 W.
Did I get it wrong?
>>
>>7809894

>>7809043
>>
Help?
>>
>>7810365
Me!
>>
>>7809927
i tried this for 555nm and checked with this website to make sure i did everything correct.. then i did the same calculation for 480nm and i got 0,012W which is either correct or we are both idiots. http://www.translatorscafe.com/cafe/EN/units-converter/illumination/9-11/lumen%2Fcentimeter%C2%B2-watt%2Fcentimeter%C2%B2_%28at_555_nm%29/
>>
>>7811317
:( please
>>
>>7811703
Thank you, for some reason it didn't show me your reply. That is a lot less than what I was hoping.
Thread replies: 18
Thread images: 2

banner
banner
[Boards: 3 / a / aco / adv / an / asp / b / biz / c / cgl / ck / cm / co / d / diy / e / fa / fit / g / gd / gif / h / hc / his / hm / hr / i / ic / int / jp / k / lgbt / lit / m / mlp / mu / n / news / o / out / p / po / pol / qa / r / r9k / s / s4s / sci / soc / sp / t / tg / toy / trash / trv / tv / u / v / vg / vp / vr / w / wg / wsg / wsr / x / y] [Home]

All trademarks and copyrights on this page are owned by their respective parties. Images uploaded are the responsibility of the Poster. Comments are owned by the Poster.
If a post contains personal/copyrighted/illegal content you can contact me at [email protected] with that post and thread number and it will be removed as soon as possible.
DMCA Content Takedown via dmca.com
All images are hosted on imgur.com, send takedown notices to them.
This is a 4chan archive - all of the content originated from them. If you need IP information for a Poster - you need to contact them. This website shows only archived content.