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 Post subject: question
PostPosted: 04.10.2002 01:06 
ok i bought 2 5v blue leds from radioshack, and im using an old keyboard wire for the power, now they get hot so im wondering if i need to use a resistor and what kind of one should i use if so.

the package the leds came in has these specs on the back

forward (supply) voltage; 5.0 typ. 6.0 max
luminous intensity (brightness)300 mcd
peak emission wavelength 430
viewing angle 24


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 Post subject:
PostPosted: 04.10.2002 05:12 
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Veteran Modder
Veteran Modder

Joined: 18.08.2002 22:38
Posts: 501
Location: Indiana, USA
that is very strange...you should not need one at all if you have them serial...but parallel they would be a little low on power...maybe there is to much current getting through to the cord and you should use a multimeter to test the voltage...them use the formula in the electricity for beginners article besides that im lost

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 Post subject:
PostPosted: 04.10.2002 06:31 
dont have a multimeter, its thru a ps/2 serial port which from my understanding is only 5v, and im connecting it to the 5v line and the ground line (and i know i am because this cheapo 10$ keyboard actually came with it written on the lines =P)

there not hot enough to melt anything but they are hot


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 Post subject:
PostPosted: 04.10.2002 06:57 
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Junior Modder
Junior Modder

Joined: 28.02.2002 01:17
Posts: 19
Location: USA
Do you have a part number?

Typically blue LEDs are 3.7V @ 20mA. They may be rated "5V max" but that doesn't make it a good idea to operate them taht way.

After enough time, they will fail, the heat is not normal at all.


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 Post subject:
PostPosted: 04.10.2002 09:06 
the only number besides the upc code is 276-311
from radio shack.it says 5v is typical, 6 is max


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 Post subject:
PostPosted: 04.10.2002 09:09 
heres the url for the item on radioshacks webpage

http://www.radioshack.com/product.asp?c ... =276%2D311


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 Post subject:
PostPosted: 04.10.2002 17:25 
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Mini Modder
Mini Modder

Joined: 01.08.2002 23:02
Posts: 30
Location: rocklin, CA, USA
i have that exact led siting in my toolbox, ready to make the glowpad with, mabye i should hold back for awhile, so i can take them back if they turn out to be too hot.


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 Post subject:
PostPosted: 05.10.2002 07:26 
i got it workin and it looks really good. i was runnin each off the 5volt line before so im suspecting that was the culprit for the heat, right now i have them both combined and runnin off the 5 volt (i guess in the correct terms it means parallel and they really arent to dim, they show up very nicely even in light


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