Michael Koblic wrote:
Since Jim Wilkins mentioned Kill-A-Watt meter here some time ago it came on
sale at Lee Valley and I got me one. I spent an interesting hour running
around the house finding out what consumes electricity while plugged in and
what does not. What surprised me were the computers.

My most recent purchase (Compaq Presario) does this:

Turned off 2.1W
Booting 60W
On but quiet 46W
Asleep 5.8W
Hibernating 1.7W

My old computer also draws about 3W while supposedly switched off.

So the questions a
1) Why is the computer drawing any power at all when turned off?

computers have soft switches. they are never off, just like a TV that has
a remote control. they use a few watts just sitting there. The power
supplies are on, in a low power mode.

2) Why is the power drawn less when hibernating then when switched off?

A 400mW difference is pretty much nothing. A hibernating computer is as
off as they can get while being unplugged. The tolerances of your chinese
power supply before and after warming up could easily cause that
difference.

A computer is a sleep state is more "on" than computer that is off, but
far less active than one that is running and doing stuff.

3) What happens to a computer which is turned off and the plug is pulled?

nothing. it uses no power and does nothing.

4) What happens with laptops? Do they draw power from their battery
continuously even when turned off?

yes. they draw power, but it's very very small- far less than the 1.7 to
2.1 watts a desktop might use when soft-off. The amount drawn is so small
it doesn't even matter in real life.

and...

Why has this stupid Windows Live Mail program suddenly decided to type ?
instead of a question mark ???

no idea.