View Single Post
  #1   Report Post  
Posted to uk.d-i-y
Skeggy Skeggy is offline
external usenet poster
 
Posts: 8
Default Mains adapter for 12V fans - back to school!

I want to set up a rack of 3 small fans (as a gadget to put under a radiator
on a cold day). I've got 3 Sharkoon 1000 PC fans, 12v 1.44 Watt each. I want
to power the rack from a normal plug-in mains adapter. I've got a 12V DC /
800mA adapter available but I'm not quite sure if this will be OK.

So delving way way back to my schooldays I think I dimly remember that:

W = VA so as W=1.44 and V=12, current will be 0.12 or 120mA for each fan.
V = iR so if V = 12 and i = 0.12 then R is 200, so resistance of each fan is
200 Ohm.

So I'm thinking I'd be OK to wire up the 3 fans in parallel, current 3 x 120
= 360mA, resistance 66 Ohm?

Also, I don't know if the 12/800mA adapter I've got is regulated, or if this
matters. It has a symbol on it like a segmented orange (a bit like
'Panaorama' logo) and also a square within a square if that helps.

Thanks,
Skeggy.