So I have a little project going, really simple. Just a computer fan that I will list the specs below and a usb 2.0 off of a iphone 4 cable.
I'm going to cut the phone charger to get the usb half and use the USB VVC +5v and the ground. I'm going to add a power switch as well. I have heard usb 2 chargers put out 500mA? The fan that I'm using only uses.08A at 12v. Do I need any type of resistors for this to not burn up the fan? I'm new to this so be kind. It seems as if the USB port will put out much more than the fan can handle.
Also if I'm just using the usb port for power and not data can I just cut the usb data+ and data- wires out of the equation? Also I want this to all be linear so could I just solder in some resistors into the circuit before the switch? What ohm resistor should I get?
Or if I'm going about this all wrong please tell me. This just seems like a simple circuit. USB to resistor to switch to fan back to usb ground.
Added (1). Update: If the usb only provides 5v and I need 12v could I use a transformer to raise the voltage? I know a usb 2 can power this tiny fan, the question is how can I do it efficiently.