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LED voltage question: 12V fan


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I have an LED fan. it is noisy and dose not push much air. before i throw it out, i thought i could use the LEDs around the system and brighten things up a bit. The fan is 12V... can i run the LEDs on 12V?

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Unless they're rated for it, no. Even then a lot of LEDs won't run at their rated voltage. Fueler found that out when he was making his custom folding rig not long ago.

 

I've got a pair of LED fans in my rig running at 5v because they were too noisy so you could try that.

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Even then a lot of LEDs won't run at their rated voltage. Fueler found that out when he was making his custom folding rig not long ago.

You couldn't be any more wrong.

 

You need current limiting resistors so you don't blow out the PN junction of the diode. If you do that, any LED will run at it's rated voltage for a very, very, very long time.

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You couldn't be any more wrong.

 

You need current limiting resistors so you don't blow out the PN junction of the diode. If you do that, any LED will run at it's rated voltage for a very, very, very long time.

I know you are right, the fan his them on its board. But, why do system lights (ie: hdd, power) not need them?

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You couldn't be any more wrong.

 

You need current limiting resistors so you don't blow out the PN junction of the diode. If you do that, any LED will run at it's rated voltage for a very, very, very long time.

Well forgive me for not being an expert in the field of LED technology and all that fancy junk. :P

 

I know you are right, the fan his them on its board. But, why do system lights (ie: hdd, power) not need them?

Probably because all that stuff required for them to run is built into the MB so it simplifies things greatly for the user.

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I know you are right, the fan his them on its board. But, why do system lights (ie: hdd, power) not need them?

They do need them, but the board limits the current itself without requiring any external resistors.

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When you hook up LED's in multiples can you wire them in series to limit the voltage?

and is it possible to use a potentiometer in place of a resistor so you could dim them down?

Series = voltage divider. You'd have to be careful with the current though.

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  • 2 weeks later...

I would personal not use them, just as easy to either goto a electronic store and purchase 12v led, yes you could run a 430 ohm res inline to bring the voltage down, but its then requires soldering really. 12v led are easy to get hold of and really cheap.

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I would personal not use them, just as easy to either goto a electronic store and purchase 12v led, yes you could run a 430 ohm res inline to bring the voltage down, but its then requires soldering really. 12v led are easy to get hold of and really cheap.
12 volt LEDs just have the resistor built in, you're paying more for the same LED.

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Yes but the costs of a standard 3.5mm led is like 15p here for either 3.5volts or 12v in red, so for it to be tidy and no res inline is better i guess for me.

Edited by M3NF

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