[plug] Anybody know how this thing works?

[Michael Holland]

On Tue, 29 Aug 2006, Daniel J. Axtens wrote:

> 12V @ 3A : P = EI = 12V * 3A = 36 Watts

That is peak, but it is average or idle that counts, plus losses in the
brick.

> Note, however, that 36W is the power the brick puts *out* - if it's is
> 50% efficient (eg old transformer style),

Those bricks are all switch mode. What was the last PC with a transformer?
 Commodore 64 maybe?

> it's 90% efficient (eg modern switchmode) that's ~40W in.

Still peak. In terms of power cost and heat, it will be much less.

> > Draws around 25W idle, 50W max, incl internal 3.5" IDE drive.
> > Dead quiet with a new fan and HDD. Perfect for many Linux appliances.

That is measured at the wall. My point is that older PCs (pre-P4) are not
the power-sucking monsters of today.

> That's power in, not power out -

My PCs obey the laws of thermodynamics.