[opensuse] [OT] How much power does a PC really consume?

On 2/18/08, Aaron Kulkis <akulkis00@xxxxxxxxxx> wrote:
Neil wrote:
On 2/18/08, Aaron Kulkis <akulkis00@xxxxxxxxxx> wrote:
James Knott wrote:
Ummm... He was talking about RMS, which implies voltage or current.
There's no such thing as RMS power.
RMS is short for Root-mean-squared
i.e. _______
/_2
V X

Sqare root (x^2) is only a way of getting the absolute version of x.
To get the actual RMS (normally used version) value of that you'd have
to average that over a full cycle.

That's why there was a bar "_" over the X.

It was there, ... someone's reply seems to have removed it.

Sorry, I did. It fell off when I fixed the shifts that apeared when
copying. Fixed it again.
I seem to have forgotten what the bar meant. I knew it when I needed
it for a test, but I lost it.
Is it the arithmic mean? The arithmic mean is a way of averaging, if
wikipedia (http://en.wikipedia.org/wiki/Arithmetic_mean) is correct.
The average of a sine (if N cycles are taken) is 0.
If the arithmic mean of a sine is plotted over a time period the
result would be the exact same sine.
The result of this would be that RMS is a useless value. It is not,
and therefore my reasoning must be flawed somewhere. Does anyone have
the time, knowledge and will to take the quest of finding this flaw? I
seem to be unable to.



RMS can apply to any function vs. time (voltage, current,
power, etc.)

RMS is just as statistical method, which is useful for making
sense of any time-variant function.

The square root of the square of power is just as much related
to power as the square root of the square of voltage is related
to voltage (NOT power).

I learned RMS was the exact calculation of the energy transmitted over
a waveform and could be seen as the average of the sinus after
rectification. The original measurement was measuring the heat of a
resistor, and therefore the power flowing through it.
I could be wrong (actually I'm quite good at that).




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