Dennis12Amplify@aol.com wrote:
>
> In a message dated 3/22/05 2:00:14 PM Central Standard Time, TexasRF@aol.com
> writes:
>
> I lost track of who said what/when;
> In a sine wave the average voltage is zero therefore average power is
> zero.In an ac circuit with sine wave voltage, average current is also zero.
> One
> could be led to think that average power is also zero?
>
>
>
> All power formulas square the voltage or current to get rid of those
> negative terms.
>
> The square of a positive number is a positive number.
>
> The square of a negative number is a positive number.
>
> The RMS value is the squareroot of the mean value all of those
> instantaneous power measurements over some finite period of time.
>
> The period of time over which the RMS value is measured can make a huge
> difference in the answer.
>
> The commonly known conversion factors only apply to pure sinewaves and
> averaging over multiples of full cycles of the waveform.
>
> As far as I am concerned, Peak measurements are the only way to go.
>
> Regards,
>
> Dennis O.
The RMS value of a power wave form is not the same as finding the RMS
voltage value, squaring it and dividing by resistance.
73
Gary K4FMX
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