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3-wire CPU cooling fan

M

mc

Jan 1, 1970
0
What is the function of the 3 wires of an Intel CPU cooling fan?

Power, ground, and RPM sense?

Is the power wire PWM modulated?
 
L

Luhan

Jan 1, 1970
0
mc said:
What is the function of the 3 wires of an Intel CPU cooling fan?

Power, ground, and RPM sense?
Yes.


Is the power wire PWM modulated?

No, it just runs on 12 volts DC.

Luhan
 
R

Reg Edwards

Jan 1, 1970
0
So if it runs from 12 volts DC, where does the 3rd wire come from?
 
N

Nico Coesel

Jan 1, 1970
0
mc said:
What is the function of the 3 wires of an Intel CPU cooling fan?

Power, ground, and RPM sense?

Yes. Yellow is usually RPM sense.
Is the power wire PWM modulated?

Power wire may be voltage regulated or PWM modulated.
 
L

Luhan

Jan 1, 1970
0
Reg said:
So if it runs from 12 volts DC, where does the 3rd wire come from?

Come from? It comes from the fan, its usually the yellow one and the
ones I tested are open collector to ground. Comprendo?

Luhan
 
M

mc

Jan 1, 1970
0
Reg Edwards said:
So if it runs from 12 volts DC, where does the 3rd wire come from?

Ground.

But the speed of my fan definitely varies with CPU temperature. Surely the
power is PWM modulated or *something*.
 
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