Hey guys,
Hoping someone might be able to help me here with some simple-ish electronic stuff, that i haven't learnt yet.
Looking at making a Fan Controller for my PC.
Making, why? Because i want a custom one that i am able to turn on/off fans, control the speed and a small LED to say if they are on/off..
I've done a fair bit of research but i can't really work out exactly what i need without asking someone..
If i run 12v power, into a switch, then through to an potentiometer, how do i determine the size of the potentiometer?
I am running these fans: Click here
which run from 12v, current is 0.14A(+-10%)
I think this working out is correct:
Vf = Fan Voltage desired
Vs = Power from the PSU (12V for the yellow wire, 5V for the red)
Rf = Fan Resistance (in Ohms)
Rr = Potentiometer Resistance needed (in Ohms)
Vf = Fan Voltage (12V, 7V, or 5V)
Va = Fan Amps (usually between .1 and .5)
Formula:
Rf = Vf/Va
Vf = Vs(Rf/(Rr+Rf))
5 = 12(120/(Rr+120))
.418 = 120/(Rr+120)
.418(Rr+120) = 120
Rr+120 = 288
Rr = 168 Ohms
So the potentiometer should be 200ohms?
What i really want to know is, will the attached diagram work - with the correct components?
what size resistor will i need after the potentiometer to run the LED's? Or is that tricky because the potentiometer is varying the current?
Appreciate any help in advanced..
Hoping someone might be able to help me here with some simple-ish electronic stuff, that i haven't learnt yet.
Looking at making a Fan Controller for my PC.
Making, why? Because i want a custom one that i am able to turn on/off fans, control the speed and a small LED to say if they are on/off..
I've done a fair bit of research but i can't really work out exactly what i need without asking someone..
If i run 12v power, into a switch, then through to an potentiometer, how do i determine the size of the potentiometer?
I am running these fans: Click here
which run from 12v, current is 0.14A(+-10%)
I think this working out is correct:
Vf = Fan Voltage desired
Vs = Power from the PSU (12V for the yellow wire, 5V for the red)
Rf = Fan Resistance (in Ohms)
Rr = Potentiometer Resistance needed (in Ohms)
Vf = Fan Voltage (12V, 7V, or 5V)
Va = Fan Amps (usually between .1 and .5)
Formula:
Rf = Vf/Va
Vf = Vs(Rf/(Rr+Rf))
5 = 12(120/(Rr+120))
.418 = 120/(Rr+120)
.418(Rr+120) = 120
Rr+120 = 288
Rr = 168 Ohms
So the potentiometer should be 200ohms?
What i really want to know is, will the attached diagram work - with the correct components?
what size resistor will i need after the potentiometer to run the LED's? Or is that tricky because the potentiometer is varying the current?
Appreciate any help in advanced..