Help Please with powering small fans

[BenBilly]

OK so I have a project in mind, basically when I'm playing games on my PC my hands tend to get really warm and sweaty so basically I have found two small fans these ones to be specific: http://www.ebay.co.uk/itm/321636289103 which I want to wire to a USB cable and make into little hand coolers. So basically I know that my USB can output 5V and 900mah so I will wire my fans in parallel because if I have my circuit rules correct then the current will be split and voltage will stay the same. Basically I want to add a variable resistor but I have no idea what size could you advise also will I need another resistor in my circuit?

Thanks,

Ben

 

[HellasTechn]

The fans in parallel will both draw the current they need to operate and voltage will be 5 volts. your usb port will be fine.

I think you will need a potentiometer of 100 Ohm to reduce speed of the fans.

the + of your fan connected to the middle pin of the potentiometer and the + of your usb port to any one of the two potentiometer pins left. Connect the third potentiometer pin to the - of your usb port together with the - of your fans.

Hope this helps.

 

[BenBilly]

OK so I wont need another resistor in my circuit then?

 

[BenBilly]

And is + black or red on my fans and is + black or red on my usb?

 

[davenn]

+ is red

 

[BenBilly]

And finally can I use a 1K Ohm potentiometer as I cannot find ones at 100 ohm's

 

[davenn]

yes you can

 

[BenBilly]

OK thankyou so much guys its really appriciated.