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USB power cooling fan?

Can my laptops usb port power a 12v .20A cooling fan if i hard wired it? I know it would be under powered, but it shouldnt harm my computer right?

 A lot of computer fans won't even run until they get up to 9volts.  Your USB will supply 5 v @ .5 a.  be sure you hook up the wires correctly.  The computer fan has three wires.  Red (Aref or positive +5v as you probably know it) Black is negative or Gnd, and the other wire is the rpm sensor, so you don't plug that wire in anywhere, the usb won't read it unless you write your own software program for it, so just let it dangle.  You won't hurt anything.  If you plug it in backwards, it simply won't run.  It won't overheat because they are brushless motors.