newbie question

Thread Starter


Joined Aug 23, 2007
Ok, I have not begun the project, yet.

My Dad was an electronics engineer that always told me I would want to know this stuff, but I rejected it. So now I regret not listening.

I would like to take a standard 5v CPU fan and run it in a portable case using a 9v battery. I am fairly certain I will need some sort of voltage regulator as to not destroy the fan.

How would one go about this?

thanks in advance


Joined Aug 9, 2007
You're right. Buy a 5v voltage regulator and connect it according to the data sheet. You can get them at radioshack or anywhere that sells electronic components.


Joined Aug 9, 2007
You need to know how much current the fan and whatever else you might have in your circuit will draw and make sure that the regulator's max current(I_max) is high enough. The datasheet for the regulator will have this.

Some regulators require other components(capacitors, resistors, etc), but the datasheet will tell you what you need.

Find your 5VDC regulator, make sure it can handle the current, some good websites for finding datasheets are or


Joined Jun 30, 2006
It all depends on the fan current. You should be able to find a "7805" three terminal regulator easily.

Some fans will run with higher voltage. Without a datasheet on the fan that's hard to determine.