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Computer Case Fan 4 pins - 2 wires

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  • Cases
  • Computers
  • Fan
  • Components
Last response: in Components
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March 20, 2014 1:26:32 PM

Hi, for an electronics project I need to control the speed of a fan via PWM, I got a computer case fan, I see it has 4 pins but only two wires come from the fan, one black and one red. Somebody knows if I can do that with that fan?
Thanks.
PD: this fan is like the one that I have. You can see in the picture the connector with 4 pins but only two wires.
http://pcel.com/hardware/disipadores-ventiladores-coole...

More about : computer case fan pins wires

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March 20, 2014 1:33:09 PM

No

You need a PWM fan and PWM fan controller to control via PWM.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

On ya typical MoBo, ONLY the CPU Headers ar PWM ..... 4 pin chassis headerss and 4 pin opt headers are NOT PWM.
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March 20, 2014 1:35:29 PM

Don't know if you can use PWM on a two pin fan, you should be able to control it by altering the voltage though. The fan you are using has PWR and GND where as a normal PWM fan has PWR, GND, sense, and control (PWM).

With the two pin fan you will not be able to sense the speed of the fan so you probably won't get accurate readings, if any at all.
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March 20, 2014 1:47:03 PM

PWM stands for pulse width modulations....using this method of control, the fan speed is controlled by applying a constant voltage and varying the lengths between the pulses. Think a skateboard ...... you lengthen the time between pushes off ya free foot you go slower.....shorten the time and ya go faster.... ya need 4 wires

VC or voltage control varies the voltage ... one ground and the voltage might vary staitcally like 3.3, 5, 7 and 12 .... or it might vary linearly between some of those numbers....really only need 2 wires .... but need a 3rd if ya wanna know what speed's it's actually going.

Then there is hybrid PWM.... Phanteks for example has a OCB that takes a PWM signal and converts it to Voltage for up to 11 fans. Up till now available only by buying a Phanteks case, the unit is supposed to be available separately as an accessory before end of this month.



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