# Power LED Light too bright



## bajer29

I found this: http://forums.bit-tech.net/showthread.php?t=144953 Does this help?


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## EVILNOK

1 option would be to paint a light color of some type of nail polish over it. Something thats somewhat see thru. If you really want to add a resistor though measure the current through it. From that you can use I x R to figure out what size resistor you would need to get 4V or 3V or w/e you need/want. I x R = V btw where I= current and R = resistance (i.e. what size resistor) in ohms.


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## raiderxx

Quote:


> Originally Posted by *EVILNOK;13227834*
> *1 option would be to paint a light color of some type of nail polish over it.* Something thats somewhat see thru. If you really want to add a resistor though measure the current through it. From that you can use I x R to figure out what size resistor you would need to get 4V or 3V or w/e you need/want. I x R = V btw where I= current and R = resistance (i.e. what size resistor) in ohms.


I have done what I bolded. I have taken out the LED, and just sharpied over it (then replaced it duh..). It worked well enough for my silverstone htpc.


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## chav3z

I like the idea of coating it with nail polish or a sharpie. Thats if i could even get at the led. Like i said im using a lian li case which are built like tanks. FYI i hooked up a variable resistor to my led, turned it up and down and totally blew out the led. Went from bright blue to dim to bright then it flashed red then it was cooked. This wasnt a power resistor just a passive one from radio shack. Cant believe i cooked that led. My solution was to drill a hole in the front of the case, put double sided tape on the other side of the hole to dim it, rigged up an led with a resistor that uses 5v (1 blue led w/ 100 ohm resistor was enough) then covered it in double sided tape so i wouldnt get any light bleeding from the front grill. I might cook that led cause it doesnt have any room to breathe. luckily there are two 120 fans in the front but not sure if theyll cool that led. It was really painful drilling a hole into brushed aluminum, friggin shame, but had to be done. Now ive got a nice non retina burning power light.


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## bajer29

Quote:


> Originally Posted by *chav3z;13264396*
> *I might cook that led cause it doesnt have any room to breathe.* luckily there are two 120 fans in the front but not sure if theyll cool that led. It was really painful drilling a hole into brushed aluminum, friggin shame, but had to be done. Now ive got a nice non retina burning power light.


LEDs are very low heat emitting. You should be fine. I don't think you'll cook it


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## InerTia*

Ha. We just covered up the LED on my friends Ultra case.


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## raiderxx

Honestly, I don't understand why they make some LEDs so bright.. I mean, when I put my computer to SLEEP, the blinking LED shouldn't be lighting up MY WHOLE ROOM.. xD


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## bajer29

They're too lazy to install a resistor?


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## craigap

On my silverstone case I took off the front panel, unscrewed the LED mounting piece then stuck a couple layers of window tint over the LED's that I picked up at Walmart for $13. Then I tinted my clock in my bedroom because that damn thing was too bright too.


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## chav3z

Quote:


> Originally Posted by *craigap;13276532*
> On my silverstone case I took off the front panel, unscrewed the LED mounting piece then stuck a couple layers of window tint over the LED's that I picked up at Walmart for $13. Then I tinted my clock in my bedroom because that damn thing was too bright too.


^good idea
Quote:


> Originally Posted by *raiderxx;13268366*
> Honestly, I don't understand why they make some LEDs so bright.. I mean, when I put my computer to SLEEP, the blinking LED shouldn't be lighting up MY WHOLE ROOM.. xD


^lol
When are micro motherboards with hdmi outputs that are intentionally built to be htpcs going to stop blinking when in sleep mode?? Its so incredibly convenient to put your pc to sleep then wake it up via wireless keyboard/ remote. The alternative is to get up from the couch and hit the power button every time you want to simply turn it on, no thanks, too lazy.









The plugs that you connect the power led wires to spits out 5v. That means a 5v led is needed and those are just way too bright. So two things, no more blinking leds when in sleep mode and no more 5v leds for power lights.


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## Doober

what I did for my bright LED was took some rough sand paper 100-250 and just lightly sanded the surface and it gave it a frosted look. This causes the light to diffuse more thus making it less bright especially from the straight on angle.

-doober

this also will look the least ghetto IMO


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## S0ULphIRE

Yeah POT = bad idea lol, LEDs can't handle big changes in current. The value of the resistor is specifically chosen. For next time:

Resistor value in ohms = (V-Vd)/Id
where V = source voltage, Vd = voltage drop across the LED, and Id is the current you want the LED to get.

edit: this site explains very well
http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_p037.shtml


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## raiderxx

Quote:


> Originally Posted by *Doober;13286636*
> what I did for my bright LED was took some rough sand paper 100-250 and just lightly sanded the surface and it gave it a frosted look. This causes the light to diffuse more thus making it less bright especially from the straight on angle.
> 
> -doober


That looks really good!

Quote:


> Originally Posted by *chav3z;13277226*
> ^lol
> When are micro motherboards with hdmi outputs that are intentionally built to be htpcs going to stop blinking when in sleep mode?? Its so incredibly convenient to put your pc to sleep then wake it up via wireless keyboard/ remote. The alternative is to get up from the couch and hit the power button every time you want to simply turn it on, no thanks, too lazy.


I think you missed my point.. I was absolutely not complaining about its' convenience, but rather the fact that the LED blinks while in sleep mode. I like to put my htpc to sleep when I go to sleep so that I can quickly check the weather in the morning. But I have had to work on dimming that darn LED because it blinks constantly while asleep. That's all.


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## S0ULphIRE

As mentioned before, it's current not the voltage that blows leds out real quick. The resistor acts as a current limiting device in this circuit, but w/e


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## Tw34k

This will explain why in more detail than I care to type.

http://led.linear1.org/why-do-i-need-a-resistor-with-an-led/
Quote:


> The long answer: LEDs are semiconductors, diodes in particular. The current flowing in an LED is an exponential function of voltage across the LED. The important part about that for you is that a small change in voltage can produce a huge change in current. That is the most important concept of this article. Resistors aren't like that. The current and voltage in a resistor are linearly related. That means that a change in voltage will produce a proportional change in current. Current versus voltage is a straight line for a resistor, but not at all for an LED.
> 
> Because of this, you can't say that LEDs have "resistance." Resistance is defined as the constant ratio of voltage to current in a resistive circuit element. Even worse, there's no real way to know exactly the relationship between current and voltage for any given LED across all possible voltages other than direct measurement. The exact relationship varies among different colors, different sizes, and even different batches from the same manufacturer. When you buy an LED, it should come with a rating that looks like this: 3.3V @ 20 mA typical. That gives you one point along the operating curve. Usually that's a safe operating point. You may get a maximum rating in addition. It may be in the form of either a voltage or current. For example, a lot of people report buying "5V blue LEDs." These are really not rated to operate continuously at 5V in most cases.


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## Glends

Quote:


> Originally Posted by *Full_Tilt;13297600*
> The LED is on its own circuit, its only going to pull as much current as it uses.
> 
> The OP thinks its a 5v LED and hooks it up to the 5v molex connector with a potentiometer and burns out the LED, then claims that "LEDs cant take voltage fluctuation, so resistors are out of the question" (dumbest thing Ive ever heard).
> 
> Most LEDs have a max voltage between 2 to >4 volts. So unless the OP got some really weird LED (very unlikely), he burned it up due to his own ignorance and instead of figuring out what he did wrong he decides to ask the arts and crafts guild how to ghetto rig it.


Sunbeam have LED's that operate at 5V, but did he have one that really did operate at 5V?


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## 222Panther222

I had the same problem with my power led in my bedroom.. Until i meet mister ducktape.


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## S0ULphIRE

Yeah the Pot would have worked, until the OP turned it down so low that there wasn't enough voltage dropping over the Pot and too much current flowing through the Led. Still not a great solution though







. Maybe a good idea would have been to put a resistor before the Led that acts as like a safe stop, then putting a Pot in front of that to dim it down if needed (or completely switch it off).


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## Tw34k

I always install a resistor to dim leds that i find to bright in the consumer electronics I buy, however I was unable to do so in the most recent router I purchased.

I simply placed layers of small squares of printer paper in between the case and led until I got the desired dimness.


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## ENTERPRISE

*It always disappoints me to see negative posts. Please assist this user. We do not know everything so do not expect the OP to know everything needed to be known for this task. Teach the member, do not berate them.

This is a friendly warning. Do it again and I will make it official.*


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## Tw34k

So you deleted my greatly informative post because I was annoyed at all the misinformation in this thread?

Makes sense.


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## ENTERPRISE

It has bee restored but I have edited out the negative elements.


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## Tw34k

The part where I made all the points that were wrong in his post to be bold text were negative elements as well I assume?

Granted I did have to make almost the entire post bold but his points were completely wrong nonetheless, would it have been acceptable had I put "Everything in bold is wrong, but hey everyone makes mistakes."

Would that have been ocn worthy? Seriously I hold my tongue so much here and self censor myself to the point of being unable to think of a way of putting things without the fear of having my post deleted on a constant basis. None of the other MANY forums I am a member of have I ever had such a issue with. It really is a bit ridiculous how hypocritical this place seems to be.


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## tpkidd3

I use Tesa Strapping Tape (black) to cover bright LEDs. It is translucent, looks good, and is really inexpensive on eBay. (Oh yeah, and it is fantastic strapping tape too.)


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## 2002dunx

1. Add a diode ( 1.2 V drop = less bright. )
2. add another led in series, again same current, half the voltage.

HTH

dunx

P.S. Blackout mode in the BIOS - PLEASE ! Or simply don't plug it in !! !!

P.P.S. What is it with all the blue LED's anyway ?


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## nazarein




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## ramicio

There is already a current-limiting resistor on the motherboard! Putting a potentiometer between the motherboard and LED isn't going to cause excess current to run to the LED, under ANY condition.


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## kennumen

Quote:


> Originally Posted by *ramicio*
> 
> There is already a current-limiting resistor on the motherboard! Putting a potentiometer between the motherboard and LED isn't going to cause excess current to run to the LED, under ANY condition.


Except the OP plugged the LED directly into a molex so that it powers on with the PC yet doesn't flash in sleep mode.


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## ladcrooks

whats a sharpie? You could also get a nail file or sand paper and gently file, rub to make it obscure


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## kennumen

Quote:


> Originally Posted by *ladcrooks*
> 
> whats a sharpie? You could also get a nail file or sand paper and gently file, rub to make it obscure


Sharpie is a brand of markers:


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## cones

Quote:


> Originally Posted by *222Panther222*
> 
> I had the same problem with my power led in my bedroom.. Until i meet mister ducktape.
> 
> 
> Spoiler: Warning: Spoiler!


Why not just unplug it from the motherboard, it's not like they have to be plugged in? That's what i did for a computer, it's on all the time and i can hear the fan anyway so i know it's still on.


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## pharcycle

I think a white LED typically has a forward voltage of 1.5v and a current about 25mA so to make it dimmer limit this to say 15mA as a first approximation (I think below 10mA and it won't light).

so from 12v you need to drop (12-1.5) = 10.5v across the resistor and you want to limit the current in the circuit to 15mA so your R = V/I (from rearranging V=IR) R = 10.5/0.015 = 700 Ohms. 700 isn't very common but 750 Ohms is so that will limit the current to 14mA which is close enough. It will only dissipate about 0.15W so a 1/4W resistor will be fine.

You could always start off with 200 or 250 ohm resistors and wire them in series one at a time until you find a brightness you're comfortable with. Cheaper and more compact than a variable resistor.

FYI a variable resistor only connected to the wiper and one end is called a rhesostat. When you connect one side to V+, the other to GND and tap off the wiper then that's called a potentiometer

.. Or just unplug it, that's what I did with my media PC

EDIT: Just done some tests on some white LEDs I have, for mine, they're dimly lit at about 100 micro amps and have a forward voltage of 3v. This would result in an in-line Resistor of 20 kilo Ohms at 5v or 90 kilo Ohms at 12v so don't buy the 200/250 Ohm resistors I suggested above as you'll be wiring them in for a long time!


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## soulbounder

How about getting some lightdims?

http://www.lightdims.com/


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