Richard Harrison wrote:
Cecil is getting at the effective value of an a-c waveform which is rms.
Slick and Cecil are talking about two different things.

I was a little sleepy when I wrote that. It didn't occur to me until
later that Slick can also use dQ/dt = 0 over a complete cycle to prove
that the average value of any AC current is zero, not just at a voltage
node. Hence the necessity for RMS values for AC.

If Slick can tell a forward wave from a traveling wave by taking one and
only one current measurement at one point on a transmission line, and
knowing nothing else about the system, he is a better man than I.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Richard Clark wrote:

wrote:
The net current is the phasor sum of the forward and reflected
currents.

...

they are flowing
in opposite directions

Uh-Huh

Now you are resorting to selective editing to completely change the
meaning. Tsk, Tsk, Richard. I can do the same thing by editing out
every "not" in your postings and replacing it by '...'.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

On Mon, 09 Feb 2004 09:01:34 -0600, Cecil Moore
wrote:

Richard Clark wrote:

wrote:
The net current is the phasor sum of the forward and reflected
currents.

...

they are flowing
in opposite directions

Uh-Huh

Now you are resorting to selective editing to completely change the
meaning. Tsk, Tsk, Richard. I can do the same thing by editing out
every "not" in your postings and replacing it by '...'.
I noticed you do not retract your statement but whine about analysis
Tsk, Tsk

Cecil Moore wrote:

Jim Kelley wrote:

From: "Cecil Moore"
2 amps added in phase with 2 amps equals 4 amps flowing
in the same direction.

You mean both directions. AC doesn't flow in just one direction. That
would be DC.

Instantaneous, Jim, instantaneous.

You say that as if you understood what it means. :-)

AC flows in one direction for 1/2 cycle
and flows in the opposite direction for the other 1/2 cycle.

Oh. I always thought it was the other way around. :-)

A 2 amp phasor
at zero degrees added to a 2 amp phasor at zero degrees equals 4 amps at
zero degrees, flowing in the same instantaneous direction as the instantaneous
phasor components. When the two component phasors are at 180 degrees, they
and their sum are flowing in the opposite direction.

So what?

73, Jim AC6XG

Cecil Moore wrote:

Here's what the standing
wave current looks like when it is not frozen in time. That's the topic of
discussion that everyone seems to want to avoid. Standing waves don't stand
still. They probably should have been called "looping waves".

http://einstein.byu.edu/~masong/HTMs...newave2EX.html

I guess that kind of thing can be exciting for the unitiated. Good for
you, Cecil!

73, Jim AC6XG

Richard Clark wrote:
I noticed you do not retract your statement but whine about analysis
Tsk, Tsk

Nothing to retract, Richard. The direction of AC current flow is merely
a convention. In a balanced transmission line system, if the differential
current is flowing toward the load in one wire, it is flowing away from
the load in the other wire. Otherwise, it would be common-mode current.
At certain times during the RF cycle, the forward current phasor and the
reflected current phasor in one wire are both pointed toward the load.
In the other wire, they are pointed toward the source. 1/2 cycle later,
things are reversed.

Draw a DC circuit with a battery and a load. In one wire, the load
current is flowing toward the load. In the other wire, the load current
is flowing away from the load toward the battery. So we reference the
wire connected to the '+' battery terminal which is carrying the current toward
the load and call the other wire a return path. But balanced AC has no such
distinction. There is no positive terminal or negative terminal on the
AC generator except by convention. Incidentally, Edison shared your
confusion.

Taking the RF generator as the reference, a freeze-frame snapshot of the
RF current maximum points up and down a matched balanced transmission line
may result in:

------------------------------------------
Source Load
------------------------------------------
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Jim Kelley wrote:

Cecil Moore wrote:
A 2 amp phasor
at zero degrees added to a 2 amp phasor at zero degrees equals 4 amps at
zero degrees, flowing in the same instantaneous direction as the instantaneous
phasor components. When the two component phasors are at 180 degrees, they
and their sum are flowing in the opposite direction.

So what?

So sometimes those two phasors are forward current and reflected current
flowing in opposite directions. The statement is still true. Think about
that for awhile.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Jim Kelley wrote:


Cecil Moore wrote:
Here's what the standing
wave current looks like when it is not frozen in time. That's the topic of
discussion that everyone seems to want to avoid. Standing waves don't stand
still. They probably should have been called "looping waves".

http://einstein.byu.edu/~masong/HTMs...newave2EX.html

I guess that kind of thing can be exciting for the unitiated. Good for
you, Cecil!

So much for some people I know who assert, "Standing waves don't move." :-)
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Cecil Moore wrote:

Jim Kelley wrote:

Cecil Moore wrote:
A 2 amp phasor
at zero degrees added to a 2 amp phasor at zero degrees equals 4 amps at
zero degrees, flowing in the same instantaneous direction as the instantaneous
phasor components. When the two component phasors are at 180 degrees, they
and their sum are flowing in the opposite direction.

So what?

So sometimes those two phasors are forward current and reflected current
flowing in opposite directions. The statement is still true. Think about
that for awhile.

If I didn't understand the difference between the instantaneous value of
an alternating current, and the direction of propagation of a wave, who
knows what I might come up with given these details. I might even come
up with a notion like yours! ;-)

73, Jim AC6XG

Cecil Moore wrote:

Jim Kelley wrote:


Cecil Moore wrote:
Here's what the standing
wave current looks like when it is not frozen in time. That's the topic of
discussion that everyone seems to want to avoid. Standing waves don't stand
still. They probably should have been called "looping waves".

http://einstein.byu.edu/~masong/HTMs...newave2EX.html

I guess that kind of thing can be exciting for the unitiated. Good for
you, Cecil!

So much for some people I know who assert, "Standing waves don't move." :-)

So much for people who don't understand the difference between current
flow, and wave propagation. :-)

73, Jim AC6XG