Standing-Wave Current vs Traveling-Wave Current
 

Keith Dysart wrote:
On Dec 28, 1:38 am, Cecil Moore wrote:
Keith Dysart wrote:
Perhaps try googling "in the limit as t approaches 0..."
So how many joules can pass a point in zero seconds?

You have descended into silliness. You are out on your
Harley doing 60 miles/hour. How far do you travel in 0
seconds?

So your point was?

But at least you now see the utility.
Nope, I don't. I don't think the concept of instantaneous
power is mentioned at all in "Optics", by Hecht.

Ahhh. The difficulty is because you don't "think" that
the concept is mentioned in Hecht. Could that be because
at 5E14 Hz, it is difficult to measure? Try a circuit
analysis or transmission line book. You will have more
luck. There is a good chance that your Ramo and Whinery
mention it. Look near where they derive
Pavg = Vrms * Irms * cos(theta)

...Keith

Ramo, Whinnery, and Van Duzer, _Fields and Waves in Communication
Electronics_: p. 16 (in derivation of Eq. 3).

Van Valkenburg, _Network Analysis_: Eq. 14-2, p. 420.

Pearson and Maler, _Introductory Circuit Analysis_: Eq. 5.42, p. 251.

Weidner & Sells, _Elementary Classical Physics, Vol. 2_: Eq. 30-10, p. 912.

_IEEE Standard Dictionary of Electrical and Electronics Terms, Third
Ed._: "Power, instantaneous (two-wire circuits)"

Roy Lewallen, W7EL

Standing-Wave Current vs Traveling-Wave Current
 

On Dec 28, 8:37*am, Roy Lewallen wrote:
Keith Dysart wrote:
On Dec 28, 1:38 am, Cecil Moore wrote:
Keith Dysart wrote:
Perhaps try googling "in the limit as t approaches 0..."
So how many joules can pass a point in zero seconds?

You have descended into silliness. You are out on your
Harley doing 60 miles/hour. How far do you travel in 0
seconds?

So your point was?

But at least you now see the utility.
Nope, I don't. I don't think the concept of instantaneous
power is mentioned at all in "Optics", by Hecht.

Ahhh. The difficulty is because you don't "think" that
the concept is mentioned in Hecht. Could that be because
at 5E14 Hz, it is difficult to measure? Try a circuit
analysis or transmission line book. You will have more
luck. There is a good chance that your Ramo and Whinery
mention it. Look near where they derive
Pavg = Vrms * Irms * cos(theta)

...Keith

Ramo, Whinnery, and Van Duzer, _Fields and Waves in Communication
Electronics_: p. 16 (in derivation of Eq. 3).

Van Valkenburg, _Network Analysis_: Eq. 14-2, p. 420.

Pearson and Maler, _Introductory Circuit Analysis_: Eq. 5.42, p. 251.

Weidner & Sells, _Elementary Classical Physics, Vol. 2_: Eq. 30-10, p. 912..

_IEEE Standard Dictionary of Electrical and Electronics Terms, Third
Ed._: "Power, instantaneous (two-wire circuits)"

Roy Lewallen, W7EL

That last one will be of particular interest to Cecil.
Its in the Seventh Edition, as well, on page 562.

Of possibly even greater interest to Cecil is the
second entry following 'instantaneous power'...

"instantaneous Poynting vector (P
(t,
r)) (of an
electromagnetic wave) The vector product of the
instantaneous electric and magnetic field vectors.
The integral of P
(t,
r) over a surface is the
instantaneous electromagnetic power flow through
the surface."

...Keith

Standing-Wave Current vs Traveling-Wave Current
 

Cecil Moore wrote:
Roger wrote:
Cecil Moore wrote:
Where did that current come
from if current cannot flow into the stub?

Stored in the 1/4 WL between the short and mouth. No more current
needed once stability is reached.

EM RF current is stored in the stub? In what form?

Come on Cecil! Let's not go around in circles! You know very well how
it happens.

On the remote chance that you are serious, I suggest you read CAREFULLY
my other postings. If you want even more information, read your own
postings from the past.

For my part, I have learned from you and your examples. For better or
worse, I feel much more comfortable in my knowledge base and ability to
communicate to others. As to the validity of my postings, each reader
will need to decide for himself, just as the reader must do for your
postings.

73, Roger, W7WKB

Standing-Wave Current vs Traveling-Wave Current
 

Keith Dysart wrote:
The cuts changed nothing about the conditions in the circuit.

This reminds me of the guru who asserted that he could
replace his 50 ohm antenna with a 50 ohm resistor
without changing the conditions.

And yet the claim is made that before the cuts there are no
reflections and after the cut there are a bunch. And yet the
conditions in the circuit are EXACTLY the same.

No, conditions are not exactly the same. Before the
cut, there were no reflections. After the cut, there
are reflections. Conditions have changed. I'll bet
the change in the natural noise pattern, which exists
in every system, could be detected at the time of
the cut.

It is no different than a connected capacitor and inductor
which will ring for ever given the appropriate initial
conditions.

If we are talking about things that can happen only in your
mind, why stop with irrelevant ringing assertions? Why not
assert that you can leap tall buildings at a single bound
(in your mind)?
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Keith Dysart wrote:

You are out on your
Harley doing 60 miles/hour. How far do you travel in 0
seconds?

So your point was?

That was my point. You made it for me.

I don't think the concept of instantaneous
power is mentioned at all in "Optics", by Hecht.

Ahhh. The difficulty is because you don't "think" that
the concept is mentioned in Hecht.

How did you manage to reply to a canceled posting?
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Keith Dysart wrote:
With the current always 0, data is not being successfully
transmitted. So with the experiment at hand, life is over.

Come to think of it, in a real-world system, the current
is indeed never zero. So if your life depended on it,
would you cut that connection that is keeping you alive?

If you really want to prove your point, you could demand
that the experiment be performed in total darkness with
the two sources turned off.
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Roy Lewallen wrote:
Ramo, Whinnery, and Van Duzer, _Fields and Waves in Communication
Electronics_: p. 16 (in derivation of Eq. 3).

Van Valkenburg, _Network Analysis_: Eq. 14-2, p. 420.

Pearson and Maler, _Introductory Circuit Analysis_: Eq. 5.42, p. 251.

Weidner & Sells, _Elementary Classical Physics, Vol. 2_: Eq. 30-10, p. 912.

_IEEE Standard Dictionary of Electrical and Electronics Terms, Third
Ed._: "Power, instantaneous (two-wire circuits)"

You guys are replying to a canceled posting.
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Keith Dysart wrote:
Of possibly even greater interest to Cecil is the
second entry following 'instantaneous power'...

What should be of interest to you guys is that you are
replying to and continuing replies to a posting that
was canceled.
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

Roger wrote:
Cecil Moore wrote:
Roger wrote:
Stored in the 1/4 WL between the short and mouth. No more current
needed once stability is reached.

EM RF current is stored in the stub? In what form?

Come on Cecil! Let's not go around in circles! You know very well how
it happens.

Here's an example using a circulator and load in
a 50 ohm system. Please think about it.

SGCL---1---2------------------------------+
\ / | 1/4
3 | WL
| everything is 50 ohms | shorted
R | stub

Are there any reflections at point '+'?

If not, how is energy stored in the stub?

If so, what causes those reflections?
--
73, Cecil http://www.w5dxp.com

Standing-Wave Current vs Traveling-Wave Current
 

On Dec 28, 10:00*am, Cecil Moore wrote:
Keith Dysart wrote:
You are out on your
Harley doing 60 miles/hour. How far do you travel in 0
seconds?

So your point was?

That was my point. You made it for me.

Ahhh. So the utility is the same utility one gets from
useful numbers like 60 miles/hour. OK.

I don't think the concept of instantaneous
power is mentioned at all in "Optics", by Hecht.
Ahhh. The difficulty is because you don't "think" that
the concept is mentioned in Hecht.

How did you manage to reply to a canceled posting?

I use http://groups.google.com to view usenet and
your post is still there.

Cancelling is a very iffy thing. Better to decide
before clicking send. Once it has entered the net
it is likely there forever. Readers and servers
may, or may not, honour future requests.

...Keith