# Voltage regulator (for fans)



## geneticmaterial (Jul 14, 2011)

Hi, 
I have a 12v 4pin Molex coable and connector that powers a small circuit board which has 6x 3pin fan outputs. 

My question is this; 

Can I add in a 12v voltage regulator to one or two of the Molex wires before the small circuit board so it effectively acts as a 'fan controller' for all 6 fans? 

one other option I'm considering is just to use a simple on/off switch. 
This switch has two prongs. 
Which wire would this go on (on the Molex) Red, Yellow or either of the two black wires? 


Thanks!! 

Dan


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## gcavan (Aug 13, 2009)

What is the function of this printed circuit board? Is it only power distribution or is it itself a controller of some sort?

PS: you would switch the +12 volts line (yellow)

Another option for you:
Easy 7V Mod for Fans | techPowerUp


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## geneticmaterial (Jul 14, 2011)

it's a simple circuit board with molex in, 6x 3pin fan outputs and there's 2 bridges which allow you to cap the voltage to 5v. Each bridge looks after 3 x 3pin fan outputs. They're all currently set to run at 12v and will remain this way. That mod's cool but I will need them all to run at 12v when I game. I want the option to either switch them off or turn them for normal computing.
If this doesn't make sense I'll post later the components if needed


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## geneticmaterial (Jul 14, 2011)

Hi, I've fitted a 12v switch to the yellow wire and this has worked (powers the fans on the 'on' position).
It's a round button switch which should illuminate when 'on' is selected.
However, it doesn't do this.
The switch is a 3 pin style.
the yellow wire goes through point 2 and exits through point 3.

Can anybody help?


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## geneticmaterial (Jul 14, 2011)

Also there's a green LED on the small circuit board which is always illuminated regardless of the position of the newly added switch.
Does this get the power from the red 5v wire?
I'm thinking that the red wire should pass through the spare point (point 1) on the 3 pin switch to get the switch to illuminate when on the 'on' position?

Actually thinking about this is seems best to ground out from the spare pin.....


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## gcavan (Aug 13, 2009)

Without seeing the circuit itself or at least its schematic, there is no way anyone can say for certain how the circuit should be powered.

Re. Switch pinout:
Are you certain it is a single throw switch?
LEDs are polarity sensitive. Do you have it connected correctly?
Look at the manufacturer's data sheet for the switch used.


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## GZ (Jan 31, 2010)

To add... Yes, the LEDs could get power from the 5V rail and that would make a bit of sense, allowing the 12V line to be dedicated to the fans.

What I don't understand is why you don't just purchase a simple fan controller. They aren't expensive and you could have independant control over each fan's speed.

Newegg.com - NZXT Sentry Mesh Fan Controller w/ Five 30 watts Channels


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