- All,

First off, while the moderators of this site ... of which I am one ... have recently discouraged critiquing of Naudin's MEG replications, I feel that if someone has something to offer in the way of criticism that is objectively based and is based on reasonably careful research then that criticism should be allowed. On that basis, I am presenting this posting which contains new information that the reader may want to consider as he evaluates Naudin's MEG replications.

Recently we have seen messages to this group that are critical of Naudin's output current measurement methods. I had problems with several statements within these messages but at that time I felt I did not have sufficient information to argue them. Recently though I made time to do some research about these concerns, and I now would like to present my discoveries to you all for your consideration.

Rather than attempting to show you what I have learned in the limited textual platform of a MEG Builders text message, I have created a .JPG file that has allowed me to incorporate both text and graphics in my report. You will find it "attached" to this message as a downloadable and hopefully on-line viewable file.

Respectfully,

Stan Mayer - --- In MEG_builders@yahoogroups.com, "Shawn Bishop"

<dragoneer58@h...> wrote:

> that number? Simple: P_scope = 1024 V * 0.1112 A / sqrt(2) = 10.2

your math is incorrect

> which every one of us here can plainly see is the wrong formula for

> power.

1024*0.1112/sqrt(2) = 80.5 not 10.2

the correct calculation is (1024*0.5*.707)*(0.1112*0.5*.707)*.707 =

10.2

I've known about this for a long time, Naudin has to. He acknowledged

possible small power measurement errors using a THS720P on his web

sight.

go to http://jnaudin.free.fr/html/ths720p.htm

But these errors don't change the bottem line that he has OU.

> The interesting thing I find is this: looking at his inputs we have

I think you mean 28 v here.

> 20 V DC in, and I_a = 0.125A. The power is:

> 28 * 0.125/sqrt(2) = 2.5 W

What you are doing here is extrapolating the value of a non-pure

sinusoid by just looking at the peak to peak values. There are spikes

in this sine wave and the scope uses sampling to calculated very

accurately the peaks and dips. So I would trust a scope on this

measurement of 111.2mArms.

> If we look at the output, dividing his output current by the factor

of

> 10 that he has measured in wrong by (using same RMS numbers as

Again you are making a big assumption on your factor of 10 here. And

> above, but dividing his output current by 10):

this assumption is based on no scientific evidence.

> So, no, Naudin cannot be trusted to have set up his scope correctly;

The Voltage and current measurements CAN be trusted. But the power

> his own data shows it irrefutably.

measurements as he admitted and posted info on, may have some small

errors which don't affect the fact that he's still getting OU.

keep probing

Ken