PC Fan Power

2 @ .16A = .32A = 320mA for the two existing fans
The adapter is good for 500mA so you have 180mA to spare.
if the new fan also draws .16A (160mA) , you're just under the limit of 500mA, so that's fine.

>possibly with a 100ohm resistor
>12v .16a
R = V/A = 12/.16 = 75 ohms (assuming the new fan is the same as the old ones)
adding a 100 ohm R would drop the fan voltage to (R/Rt)*V = (75/175)*12 = 5.14Volts, and reduce the current to 12/175 = 69mA.

12V, 160mA = 1.92watts
5.14V, 69mA = 0.35 watts
Don't know how well thet would work.

>kill a watt says it uses a .7 power factor and 400mA from the outlet.
Meaningless. It includes the power consumed by the adapter which is unrelated to the output current capability of 500mA.

File: wire-to-5v.png (3KB, 446x300px) Image search: [Google]

3KB, 446x300px

>>1133968

If in a pc just wire the fan to 5v

>>1135429
5V may not be enough to spin some fans, an alternative is to wire it between 12 and 5, so you get 7V