[AMPS] RMS Power

[2]

>
>Hi Marv,
>
>The average voltage of a sine wave is 0. That is why the RMS value
>is used in power calculations. For a sine wave the RMS voltage is
>0.707 times the peak voltage. 
>
However, polarity counts for naught when calculting watts.   Average V of 
a sinewave is c. 0.636 of E-peak.  

cheers, Mike
> 
>----- Original Message ----- 
>From: "Radio WC6W" <wc6w@juno.com>
>To: <billydeanward@hotmail.com>; <amps@contesting.com>
>Sent: Thursday, June 28, 2001 7:20 AM
>Subject: Re: [AMPS] RMS Power
>
>
>> 
>> On Thu, 28 Jun 2001 05:32:16 -0000 "Billy Ward"
>> <billydeanward@hotmail.com> writes:
>> >
>> >[WC6W]
>> >The Bird 43 (without a peak reading module) is an average reading
>> >meter.
>> >
>> >[Billy]
>> >I thought that the Bird 43 was an RMS meter without the peak reading 
>> >module. 
>> >  RMS and average are not the same?
>> >
>> >Billy
>> >
>> >_________________________________________________________________
>> 
>> Hi Billy,
>>    No, they usually aren't.   
>> 
>>    For a sine wave, average voltage is equal to .9 * RMS voltage.   The
>> factor is different for other waveshapes.  Try figuring the numbers on a
>> triangle wave for... fun. :-)
>> 
>>    The Bird scale is calibrated to read "power" (RMS voltage squared /
>> line R) even though it is driven by average voltage... accurate as long
>> as it is measuring a sine wave in a 50 ohm resistive system as Maury
>> noted.
>> 
>> 73 & Good morning,
>>    Marv  WC6W  
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> *
>> 
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>
>
>
>--
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>
>


-  R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.  
end


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