Hello people,
Can somebody help me to supply 12V DC power to another 12V CPU fan? I'm already using a 12V power supply to the Arduino UNO board
Can't you just tap into the lines?
KaviduAloka:
Can somebody help me to supply 12V DC power to another 12V CPU fan? I'm already using a 12V power supply to the Arduino UNO board
Another fan?? Are you using more than one of those fans?
What is the current rating of your 12V brushless pc fan?
What is the actual current output capability of your 12V DC power supply?
What is the current consumption of your Arduino setup?
Thank you very much for the replies. Actually, I have given the power to the Arduino UNO board using a 12V power supply. And I want an output of same 12V from the board to a CPU fan...
KaviduAloka:
I have given the power to the Arduino UNO board using a 12V power supply. And I want an output of same 12V from the board to a CPU fan...
Yeah we got that, hence my reply #1
Yeahh... But it gives the direct current to the fan. That's not what I really want. I want to switch the fan using the board. Hope you understand
KaviduAloka:
Yeahh... But it gives the direct current to the fan. That's not what I really want. I want to switch the fan using the board. Hope you understand
I do now: that's very different from what you said earlier. Controlling and Powering are not the same.
You'll need a transistor like a logic level MOSFET to act as the electronic switch, with one leg controlled by an Arduino pin to let de/activate the transistor which in turn will switch the fan off and on.
Have a search here for something like "Arduino mosfet" and I'm sure you'll find some examples.
KaviduAloka:
Thank you very much for the replies. Actually, I have given the power to the Arduino UNO board using a 12V power supply. And I want an output of same 12V from the board to a CPU fan...
You haven't answered my previous questions. Anyway now your requirement has suddenly changed from sharing power supply to powering it from your board.
KaviduAloka:
Yeahh... But it gives the direct current to the fan. That's not what I really want. I want to switch the fan using the board. Hope you understand
Now you're requirement changed again. Now you want to switch the fan on and off with your arduino, have your previous requirements been solved or did you abandon them?
Noobian:
have your previous requirements been solved or did you abandon them?
I think OP's merely refining how he's stating his requirement.
Thank you guys for the replies. I will try that Arduino mosfet. And I will update you guys ASAP...
KaviduAloka:
Simply this is what I really want...
Not possible. You can't power your fan from your board since it needs 12V 100ma+ and Arduino can only give 5V 20mA through it's pins.
Noobian:
Not possible. You can't power your fan from your board since it needs 12V 100ma+ and Arduino can only give 5V 20mA through it's pins.
That's true, but OP's pic isn't actually what he asked for in words in #5, my bold:
I want to switch the fan using the board
Have a look here.
The 12V at the top for the fan, is just a tap from the supply to the Arduino.
Here's a rough scribble of how to do that. Apologies to Nick Gammon for messing up his great schematic.
kenwood120s:
That's true, but OP's pic isn't actually what he asked for in words in #5, my bold:
I'm a bit confused here. In #3 he said
KaviduAloka:
And I want an output of same 12V from the board to a CPU fan...
@KaviduAloka You may want to try this. I'm assuming your fan only uses 100mA so you can use a TIP122 transistor as a switch along with a 1K resistor and a flyback diode across the fan.
Thank you very much guys for all these replies...!!! I'll try one of these... It's nice to learn that.
Cheers...!!! 
Those two replies are pretty similar btw; both use a transistor. Nick Gammon's one with my scribble is a mosfet, the other is a bjt.
The mosfet one needs that 10k resistor which the bjt one doesn't; that's due to the nature of how a mosfet works.
But the bjt version should have the flyback diode shown on the mosfet version: that's always required when switching inductive loads like motors or solenoids.
edit: I see Noobian added the diode before I posted this. Netiquette says when you make an edit like that, you should say it's an edit (eg edit: added flyback diode) , not just sneak it in. It's even better to add a new pic in a later post, in case someone was already working off the old pic and didn't notice it was changed.
kenwood120s:
edit: I see Noobian added the diode before I posted this. Netiquette says when you make an edit like that, you should say it's an edit (eg edit: added flyback diode) , not just sneak it in. It's even better to add a new pic in a later post, in case someone was already working off the old pic and didn't notice it was changed.
Sorry about that, will do that next time I make a change. Also my Image hosting site has some issues and the pic is not showing now