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#7
November 8th 03, 12:28 AM
 Dave Bushong Posts: n/a

RHF wrote:

SL,

To be 'consistant' in your Logic of using "Five Significant Digits":

Would be: 120.00 V * 1.4142 = 169.704 Rounded 'down' to 169.70

NOT: 120 V * 1.421356237~ = 169.705627484~ Rounded 'up' to 169.71

- - - When 'rounded' to Whole Numbers the Answer would be 170.

But then again, how does one really, truly, factually claim that "170"
is 'round' to "Two Significant Digits" using Three Numbers ? ? ?

Hmmm... those answers are fine (close, but only that) for textbook
examples of how to convert numbers, assuming a pure sine wave. They are
great for teachers (and those who have learned only from teachers). In
real life, if the answer comes out to 169.705627484, remember that the
real-world value can plus-or-minus a few volts.

It's a lot like saying that "Observers estimate that the fire was at
least a mile, or 1.609347219 kilometers, away."

Have you ever done it? I mean, looked at a scope, stuck the probe in
the wall socket, and measured the line voltage? Is it a pure sine wave?
(answer: no, and no, I suppose). It's a complex power waveform.

So, do you know how to integrate a complex waveform such as a sine wave
with various spike interference present, in order to know the true RMS?
Does it even matter, if you are lighting up a light bulb?

By the way, this thread was so distorted that I don't know who is who,
and it is obviously a ****ing contest, so if I mistakenly pointed out
the idiocy, or replying to the idiocy, I apologize ahead of time.

The good part is that one or more of these guys will flame me without
facts, and that will answer the original question.