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### Author Topic: Fan controller  (Read 26309 times)

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#### kam

• Hero Member
• Posts: 1849
##### Re: Fan controller
« Reply #30 on: June 25, 2012, 11:56:04 AM »
if the supply has ripples due to the switching of the mosfet, then yes, you will be needing a larger capacitor indeed.

#### ketske

• Newbie
• Posts: 34
##### Re: Fan controller
« Reply #31 on: June 25, 2012, 12:19:43 PM »
if the supply has ripples due to the switching of the mosfet, then yes, you will be needing a larger capacitor indeed.
Allright, and a ceramic capacitor?
So an higher 47nF ceramic and  how can i calculate this to get the correct electrolytic cap ?

« Last Edit: June 25, 2012, 16:07:07 PM by ketske »

#### kam

• Hero Member
• Posts: 1849
##### Re: Fan controller
« Reply #32 on: June 25, 2012, 16:02:56 PM »
for the electrolytic, in case that you have ripples, it is ok to use one 1uF and one 1000uF... Typical values.

#### ketske

• Newbie
• Posts: 34
##### Re: Fan controller
« Reply #33 on: June 25, 2012, 17:11:30 PM »
for the electrolytic, in case that you have ripples, it is ok to use one 1uF and one 1000uF... Typical values.

i think this is running good but only i cnat get the full speed and what you said the ripples.
so with these2 changed it would be fine?

besides the ps3 pwm fan
if a attach this to a 0.16a 12v fan it will start but  wont turn , i think this happens because this circuit has too much resistance?

#### kam

• Hero Member
• Posts: 1849
##### Re: Fan controller
« Reply #34 on: June 25, 2012, 20:10:50 PM »
hmmmm why don't you post some photos to have a look?

The circuit has minimum resistance. This mosfet has much less than 1 ohm turn-on resistance.

#### kam

• Hero Member
• Posts: 1849
##### Re: Fan controller
« Reply #35 on: June 25, 2012, 22:42:25 PM »
from what i can see, both diodes point to the same direction. If this is true, then this is the problem. Doublecheck the diodes, this is the most common mistake that people do with this circuit.
The mosfet is very had to kill unless you wire it wrong.

I suggest you (always) prototype your circuits on breadboard, this way you cave the chance to 1. select the final part values and 2. get to see if the circuit fits your needs

It is impossible to see what is wrong with these pictures...  Get a breadboard and try this again. It will eventually work.

#### ketske

• Newbie
• Posts: 34
##### Re: Fan controller
« Reply #36 on: June 26, 2012, 12:40:15 PM »
allright ive got it work now , but i think a wire get off and the mossfet's drain or gate gets a lil spark.
so i tested the mossfet with gate and source on the ground and 12 on the drain , when it lets 12v trough the gate or source, its broken , right?
so i mount it back and i cant get control it just spins 100%
and i tested the 555 like u said and the fan spins smooth to 100%
« Last Edit: June 26, 2012, 13:06:23 PM by ketske »

#### kam

• Hero Member
• Posts: 1849
##### Re: Fan controller
« Reply #37 on: June 26, 2012, 15:20:17 PM »
the mosfet probably has waved bye bye.... What was the problem? the diodes?

#### ketske

• Newbie
• Posts: 34
##### Re: Fan controller
« Reply #38 on: June 26, 2012, 15:35:56 PM »
the mosfet probably has waved bye bye.... What was the problem? the diodes?
mmm no a lil wire loosed i guess , lill crappy tho, but now ive done a lill homework and i did this succesfully
next im gonna do some more serach work to bring a simple a pot on it so , like this diagram on pcb.

with this im happy for now ..

Kam i very appreciated your attention, i hope i am wasn't too anoyying to you :-p!
And until next time!

keep up the good work! :-)

kenneth