On Thu, 28 Jun 2001 17:20:27 -0700 "Mike" <W4EF@dellroy.com> writes:
>
>Well, okay if your talking about the average "magnitude" of the voltage,
then you are
>correct, Vavg = 2/pi *Epk = 0.636*Epk = 0.9*Erms. Now I understand what
Marv was
>getting at.
>
>73 de Mike, W4EF...........
Hi Mike,
Yes!
The point being that a (continuous) sine wave (or any other
sufficiently continuous waveform) whose average (absolute) value is .9 of
its RMS value will read correctly on a Bird 43 Wattmeter (or meter of
similar design).
73 & Good evening,
Marv WC6W
>
>----- Original Message -----
>From: "2" <2@vc.net>
>To: "Mike" <W4EF@dellroy.com>; "AMPS" <amps@contesting.com>
>Sent: Thursday, June 28, 2001 11:46 AM
>Subject: Re: [AMPS] RMS Power
>
>
>>
>> >
>> >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
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> *
>> >>
>> >> ________________________________________________________________
>> >> GET INTERNET ACCESS FROM JUNO!
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>> >>
>> >> --
>> >> FAQ on WWW: http://www.contesting.com/FAQ/amps
>> >> Submissions: amps@contesting.com
>> >> Administrative requests: amps-REQUEST@contesting.com
>> >> Problems: owner-amps@contesting.com
>> >>
>> >
>> >
>> >
>> >--
>> >FAQ on WWW: http://www.contesting.com/FAQ/amps
>> >Submissions: amps@contesting.com
>> >Administrative requests: amps-REQUEST@contesting.com
>> >Problems: owner-amps@contesting.com
>> >
>> >
>>
>>
>> - R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
>> end
>>
>>
>> --
>> FAQ on WWW: http://www.contesting.com/FAQ/amps
>> Submissions: amps@contesting.com
>> Administrative requests: amps-REQUEST@contesting.com
>> Problems: owner-amps@contesting.com
>>
>
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
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