On Fri, 2008-04-25 at 01:45 +1200, Apptech wrote:
> As concern about "wasted" energy assumes ludicrous 
> proportions such things will become important.

Will become yes. As it stands though, they are just using resistors,
disagree with it all you want, that's what's out there.

> You probably need about 10% losses to stabilise a series 
> string - maybe more depending on required tolerable voltage 
> variations.
> 
> A linear constant current source is better power wise than a 
> resistor for variable voltage, 

Umm, mains is mostly fixed in voltage, so a linear regulator will have
very little benefit.

> and a simple buck converter 
> better again.

But at what cost? Say instead of 90% efficiency you get 95% with a buck.
Considering how little power these things need to begin with the energy
savings is almost trivial. 

Couple that with something that people ALWAYS forget: how much more
energy is need to PRODUCE and DISPOSE of the buck converter components,
verses a simple resistor? The amount of energy something uses during
it's lifetime isn't just the power used to operate it, you MUST include
the "lifecycle", the energy needed to produce it, and to properly
dispose of it.

Semiconductor production is quite energy intensive.

TTYL
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist