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5v LEDs

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Serraph

Member
Joined
Oct 4, 2002
Location
Corinth, MS
Different color leds will operate at different voltages. You'll need a resistor to step down the voltage to the led but it's a simple calculation. (voltage source - led voltage) / led current = resistor value

So a blue led that runs at 3.5 V and 30 milliamps using the 5 volt line of a power supply would need a:

(5 - 3.5) / .03 = 50 ohm resistor
 
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Supertrucker

Way Too Jealous Member
Joined
Dec 13, 2002
Location
Southern California
my 3.5v(max4.x volt, according to the package) are really bright at 5v:D
i dont know how long they will live, but i did the molex mod for my 1 hdd and two roms and those three leds + an antec blue psu are all but lighting up the inside of my case. i may just get a couple more leds instead of a cold cathode
 

Wiseass

Member
Joined
Aug 8, 2001
Location
Aurora, Illinois
Serraph said:
Different color leds will operate at different voltages. You'll need a resistor to step down the voltage to the led but it's a simple calculation. (voltage source - led voltage) / led current = resistor value

So a blue led that runs at 3.5 V and 30 milliamps using the 5 volt line of a power supply would need a:

(5 - 1.5) / .03 = 50 ohm resistor

how come when I did the math it comes up to 116.66666666666667?
 

modenaf1

Member
Joined
Mar 1, 2003
Location
the terran system
speaking of leds, when i tried to mod my mouse with one, In certain spots, it would lite up green, and in others it would be oragnge and get really really really hot, or maybe that was just me electricuting myself.
 

CrashOveride

Member
Joined
Jun 22, 2002
Location
Beijing, China
i checked the radioshck site... only 1 colored LED i saw maxed out at or above 5v... unless i missed em wich wouldnt surprise me... and none of them are very bright- i would check www.case-mod.com for cool LED's and then find what kinda resistor you need:D
 
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Serraph

Member
Joined
Oct 4, 2002
Location
Corinth, MS
Rocko[DPC] said:


Because he meant to say (5-3.5)/.03

Yep that's what I meant. Fixed. Don't you hate when you are thinking something and write that down instead of what you're supposed to. :)
 
OP
H

HashX

Registered
Joined
Feb 16, 2003
Location
Maryland
wow guys thanks, i couldn't pop on for awhile - i know how to use the resistors its just a convienience issue - most everything we do is off of 5v lines - either from power supply or from usb

it looks like eled only had one green led that was 5v and didn't have an integrated resistor

it appears that all of (just one) radio shacks 5v'ers (only cause its fun to say) come with a holder for like 2.50 -- i didnt see any in the store ...

i always hear (read) people talking (writing) about these all the time - where are you getting them>?

(ebay is a no go for now too - but that could change)