The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: Tony Williams
Subject: Re: Watt Meter Project....Attn Win
Date: Sun, 22 Dec 2002 13:28:36 +0000 (GMT)
NNTP-Posting-Date: Sun, 22 Dec 2002 13:45:17 +0000 (UTC)
User-Agent: Pluto/1.14i (RISC-OS/3.60)
In article ,
R. Lewis wrote:
> You are correct in that I wrote VA as a lazy mans way of writing
> sigma di*dv but what I still cannot see is how the power in a
> reactive load can be deduced from looking only at two consecutive
> quadrants. No problem as long as the load is not reactive - make
> the assumption that the each half wave is the same as the next -
> but is it not the point with complex loads that this is not so -
> and cannot be so else they would not be complex!
Think of it instead as a synchronous demodulator,
albeit operating on half-waves. Sync demod lifts
out the component of current that is inphase with
the voltage. If the waveshapes are decent sinewaves
then the averaged dc should be a good representation
of the real power.
I'm not so sure of the validity of the measurements
where the waveshape has a high harmonic content though.
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup