[Amps] Measuring RF Power

[R.Measures]

On Mar 22, 2005, at 12:25 PM, Gary Schafer wrote:

> If what you say was true then there would never be any power into our 
> transmission lines.
>
> Average power is not zero simply because there is no negative power.
>
> There is only RMS voltage and RMS current. No RMS power.

My sis-in-law's electric water heater uses 240V-rms at c. 30A-rms.  If 
there is no RMS power, why does the water get hot?
>
> Peak voltage is 1.414 times RMS voltage. Those conversions don't work 
> with power.
>
> 73
> Gary  K4FMX
>
> TexasRF at aol.com wrote:
>>  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?
>>  There is an RMS value related to peak value divided by square root 
>> of 2;  same as peak times .707.
>> There is an effective value related to equivalent d.c. value which is 
>> also  equal to the rms value.
>>  See Radio Handbook Alternating Circuits, Impedance and Resonant 
>> Circuits  Chapter, pg 3-3 in the 23rd Edition.
>>  Historically we have always referred to peak power as 1.414 times 
>> rms power  but not sure of the basis for this. Perhaps someone else 
>> knows.
>>  73/k5gw
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>
>
>
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org