MB Power Brick (was: PowerMacs EOLed (and a wee announcement)

[Christopher Bort]

On 10/17/06 at 12:11, Roland Torres wrote:

> On Oct 17, 2006, at 11:34 AM, Shawn Erickson wrote:
> 
> > In other words the skin of the power brick is the
> > cooling surface which is thermally connected to the components inside
> > using various methods (heat conductive mounts, PCB layers, etc.).
> 
> Hah, plastic is not a good thermal conductor. Just look up the  
> specific heat content of materials; plastics are pretty near the  
> bottom, so (to state the obvious) it's not a good design choice to  
> use plastic for this purpose!

Sorry, but that's not obvious at all. Without knowing the specific design
parameters of this particular power brick, we can't judge whether it's a
good choice or not. If the unit is designed so that its skin is a cooling
surface, don't you suppose that perhaps the engineer(s) who designed it
would have taken the material's thermal properties into account and
calculated that it is sufficient for this application?

> > I see no indication that Apple's power bricks are operating outside of
> > the design limits of the component they use in them.
> 
> Neither do I. But their function is not enhanced by cramming the  
> components into a tiny sealed plastic case, and running them near  
> full output.

And you know this because you have access to the design specs, or are you
speculating without any real data just to be contrary? In any case, the
power brick for my MacBook, which is usually in use for a minimum of eight
hours every day, gets warm but never too hot to hold comfortably. That is
to say, without taking objective measurements, it seems to be dissipating
heat just fine and there's no reason to believe that there's anything wrong
with its design.

-- 
Christopher Bort
<topher at thehundredacre.net>
<http://www.thehundredacre.net/>