[LINK] Blackle increases power use with small LCD monitors

[Bernard Robertson-Dunn]

Tom Worthington wrote:

> At 06:16 PM 4/12/2007, Kim Holburn wrote:
> The power they supply can be calculated from what is written on the 
> unit. So for example the ASUS Eee PC has a 9.5 Volt 2.315 Amp supply. So 
> 9.5 X 2.315 = 22 Watts.

I'm not sure this is a true statement

What is written on the unit is probably a rating. ie it can safely 
deliver 9.5 volts at 2.315 amps. What it doesn't tell you is how much 
power it draws from the mains and how much it disipates as heat when 
delivering 2.315 amps.

It is likely that the transformer drops the mains to something greater 
than 12V and is then regulatd to 9.5V. So with losses in the transformer 
and the loss in regulating the voltage to 9.5V I doubt if the efficiency 
is any better than about 75%.

That means that the ASUS Eee PC is probably drawing closer to 30 Watts

-- 

Regards
brd

Bernard Robertson-Dunn
Sydney Australia
brd at iimetro.com.au