View Full Version : anyone know the voltage for the led's
05-31-2011, 09:35 PM
that come on a compaq case? trying to rig a power light and i think I might have over volted it. it came on for a split second and went out. currently conneted to the 12v rail. should i hook the other to the 5 v? or does it take less?:help:
05-31-2011, 09:40 PM
To my best knowledge it is between 1.5 and 5v most modern mobos that I have checked were 5V.
05-31-2011, 09:48 PM
so a 2005 model compaq desktop "should" have 5v lights? cause i only have one left till I find some more, or another old case to raid. sucks i didn''t think to ask cause i wanted the green one, now I get yellow.
that worked thank you
05-31-2011, 10:01 PM
Anytime I can!
05-31-2011, 10:39 PM
tuns out it's kinda orange when it's on. an ugly orange at that
05-31-2011, 10:40 PM
hopefully it fits in the theme of the case
05-31-2011, 10:46 PM
theme? cases have themes? yeah, it fits in the "your gonna do what I want or go in the garbage" theme. my case has been modded for functionality. with little to no thought to looks. the same way I treated my work truck when i had it.
if you look up my previous case modding thread you'll see prime examples of what I'm talking about. I gutted holes where I needed them for airflow and cooling., and slapped a wire grill over them to protect the cats, and kids. and me from my own stupidity.
06-01-2011, 01:28 AM
theme? cases have themes? yeah, it fits in the "your gonna do what I want or go in the garbage" theme.
06-01-2011, 02:52 PM
most leds operate from 1.5-3 volts depending on the color.
06-01-2011, 06:30 PM
these are the plastic coated ones used on almost any case how long will they survive running at 5v?
06-01-2011, 07:11 PM
He is right about the different color leds requireing diff voltage. The range technically is 1.6v to 4.6v Check ultraviolet leds 4.6v. Infrared are 1.6.
So for your led. Orange 2.03 < ΔV < 2.10 Yellow 2.10 < ΔV < 2.18 would be proper volts.
At 5v you should be fine for quite a long time just dont hook it to a 12v 12+amp rail again. They need like 30 something mW to run.
06-01-2011, 07:36 PM
if the plastic is colored, how do you tell what color the led in it is? if they use colored plasitc to make the light blue or green or whatever, wouldn't the led in it be white, like my flashlight?
and i think I still have a couple UV led's somewhere...
06-01-2011, 09:03 PM
even though they are colored the diode usually emits the same color. unless over or under volted
06-02-2011, 03:25 AM
that might explain my yellow led turning orange. kinda burnt orange. redish brown even.
I'm handy with a soldering iron. what do i add to the circut to cut it to 3.3 volts. this seems to be the most common voltage for any of the leds I looked up.
06-02-2011, 03:30 AM
The colored plastic typically matches the LED color. Clear, pale blue usually indicates an infrared LED.
Standard LEDs can easily accept up to 24 volts, but it's complicated. What burns out an LED is heat, produced by electrical CURRENT. Current is the "rate of flow of electric charge" flowing through a circuit. Voltage is equivalent to "pressure". Typically, what keeps an LED from burning out is a current-limiting resistor (or the inherent resistance of a battery). This resistor restricts the electric flow, generating heat and protecting the LED. Therefore, the correct resistance to protect an LED depends on the applied voltage.
Also complicating things further: There's no single "correct" answer; a lower resistance allows more current to flow which means the LED glows brighter (as long as it doesn't burn up). A higher resistance will restrict the current and produce less light from the LED. (This is why you can find LED resistance calculators on the 'net.)
The takeaway: You need to know the circuit, to determine what LED resistance / current / voltage is appropriate. If you're really interested in working with electric circuits, consider buying an inexpensive multimeter and learn how to use it - there's lots of great electronics info on the 'net.
06-02-2011, 03:38 AM
what i want is to to know how you typed all that so fast.
no really, all i want is to use an led as a power on indicator. i want it to last. but i think I figureout a way to do this with no modifications. since the 24 pin connector only has 2 pins in it ATM to tell it turn on/off then the 3.3 volt pin is open. so I'll just connect to that.
I think that should work fine. if not I'll just raid a few more old cases for the lights till i figure it out.
06-02-2011, 03:53 AM
if it is a blue or white LED it might last for a while the red/green/amber/orange/yellow LEDs not so much. The blue/white/aqua colors require anywhere from 2.6-3 volts to operate, the others are like in the 1.5-2 voltage range I have to wait for my roommate to get off the XCrack 360 to verify this.
06-02-2011, 04:11 AM
frozen cpu sell them in all colors at 3.3 volts. the copy of "getting started in electronics" from radio shack, that I just pulled off the shelf give a voltage range for each color. none of which is over 3.0 volts. it does however give a formula for getting them to work by using a resistor. and uses 5.0 volts a the referance point in the example.
series resistance = supply volts - led voltage / led current. so what i need to figure out is how many milli amps my led needs as the led current.
the example states 5v - 1.7v /0.01 (10 milliamps) =330 ohms
so with a few extras and some playing around i should be able to get a stable led functioning. i have a bunch of red ones here but they are 3mm, and the mounts i stole from the case are 5mm but i can use them to test with i guess.
06-04-2011, 08:14 PM
06-04-2011, 09:09 PM
found a better way....
2709 as soon as i can get some batteries I'll take a better pic of it. but that TT emblem is my "the power is on" indicator.
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