What does RMS Mean
01-04-2007, 01:44 AM
#1
What does RMS Mean
Hey guys, I have seen a lot of questions, and answers regarding RMS wattage, and nobody has described what it actually means, so I thought I'd give a little insight.
RMS is an acronym for "Root Mean Square",
That might not be the clearest way of putting it though. If we take into acount that the Mean of 2 numbers is simply the average of the two, the abreviation makes a little more sense. We are taking the Root of the average of the Squares of the Voltage.
RMS is the only true way to measure AC voltage acurately.
Hope that clears up a few qusetions regarding this odd acronym.
regards, Mark
RMS is an acronym for "Root Mean Square",
That might not be the clearest way of putting it though. If we take into acount that the Mean of 2 numbers is simply the average of the two, the abreviation makes a little more sense. We are taking the Root of the average of the Squares of the Voltage.
RMS is the only true way to measure AC voltage acurately.
Hope that clears up a few qusetions regarding this odd acronym.
regards, Mark
Last edited by SQ Civic; 01-04-2007 at 05:16 AM.
01-04-2007, 05:14 AM
#2
TO expand on mark's point, Root Mean Square is how you arrive at the number.
The problem is that the average of any sine wave is exactly Zero, because it will have equal parts above zero, and below. so what mathematicians did is decided to square the value at every point on the sine wave, because the square of a negative is always positive, and the square of a positive is always positive.
So after they SQUAREed the values, they took the average or MEAN value, and then found the square ROOT of that value, which is how we arrive at the RMS value of a sine wave.
The problem is that the average of any sine wave is exactly Zero, because it will have equal parts above zero, and below. so what mathematicians did is decided to square the value at every point on the sine wave, because the square of a negative is always positive, and the square of a positive is always positive.
So after they SQUAREed the values, they took the average or MEAN value, and then found the square ROOT of that value, which is how we arrive at the RMS value of a sine wave.
01-13-2007, 01:41 PM
#7
errr..... well there really is no such thing as RMS 'wattage' (power)... I think thats been covered before though, so I wont go there...
Any waveform or sound you can come up with is a collection of sine waves...... and provided your meter has wide enough bandwidth you can most certainly find an RMS voltage or current for any AC signal.....
Any waveform or sound you can come up with is a collection of sine waves...... and provided your meter has wide enough bandwidth you can most certainly find an RMS voltage or current for any AC signal.....
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