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Old March 7th 04, 11:19 PM
Old Ed
 
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Don't have a copy of said dictionary at hand.

"Cecil Moore" wrote in message
...
Gene Fuller wrote:
There is no "proof" that non-dissipative resistance exists. This term
is a "definition", not something that can be proven.


Gene, seems to me that the necessity of two "non-equivalent"
definitions of "resistance" in the IEEE dictionary is proof
of something that needs differentiating in the language.

Did trees exist before the word "tree" was invented?
--
73, Cecil http://www.qsl.net/w5dxp



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  #82   Report Post  
Old March 8th 04, 12:43 AM
Reg Edwards
 
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The phrase "None-dissipative resistance" is utter nonsence.

It serves no practical purpose whatsover. It has no educational value such
as imaginary jX.

Its very mention serves only to confuse, particularly to apprentices in the
electrical engineering trade.

As a practicing engineer for nigh on 60 years I had never heard of it until
the old wives and authors on this newsgroup began wittering about it for the
sole but futile purpose of demonstrating how knowledgeable they are and for
making money. I have managed very well without it thank you.

They are from the same class as they who consider radiation from a dipole is
mainly from the middle third. But I suppose they must be tolerated. Live
and let live, eh!

And, to the particular individual concerned, I managed to write this in
plain English without swallowing Websters Morocco-bound Dictionary.

Having got that off my chest I will finish this nice glass of Californian
Red (yes, American. I don't believe in trade sanctions) and retire to bed.
Good night everybody.
----
Reg.


  #83   Report Post  
Old March 8th 04, 12:52 AM
Dave Shrader
 
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Reg Edwards wrote:

SNIPPED

Having got that off my chest I will finish this nice glass of Californian
Red (yes, American. I don't believe in trade sanctions) and retire to bed.
Good night everybody.
----
Reg.


Good morning Reg,

Oh Reg: I've spent more than a year building a mental image of the
gentleman englishman only to have it destroyed by "Californian Red".

A nice continental Sherry would preserve my image!

I use only a gram or two of altar wine once a day in the morning! To
each his own, but you do have to rebuild my image of you. :-)

  #84   Report Post  
Old March 8th 04, 02:37 AM
Bob
 
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Reg,

Well said! Now go treat yourself to a Wyndham Estates Bin 555 Shiraz,
Tyrell's Long Flat, or perhaps a Cesari Amarone Valpolicella.

(what particular Californian Red were you enjoying? There's a Corbett
Canyon that's not too bad, but I have found very few that are worthy of
mention.)

B.

  #85   Report Post  
Old March 8th 04, 03:33 PM
Cecil Moore
 
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"Reg Edwards" wrote:
The phrase "None-dissipative resistance" is utter nonsence.


It is my understanding that if the reactance of the characteristic impedance
of a transmission line is zero, the characteristic impedance is non-dissipative
and a pure resistance.

The IEEE's "resistance = real part of impedance" is indeed often non-dissipative.
If a voltage is in phase with a current, the V/I ratio is a resistance but not
necessarily dissipative. That's why the IEEE has two definitions of "resistance".
--
73, Cecil, W5DXP


  #86   Report Post  
Old March 8th 04, 08:25 PM
Steve Nosko
 
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Cute...

"Richard Clark" wrote in message
...
On Sat, 06 Mar 2004 18:19:20 -0600, Cecil Moore
wrote:
Richard, how much do you pay for your blinders?

Trying to sell yours?



  #87   Report Post  
Old March 8th 04, 09:04 PM
Steve Nosko
 
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I wonder what happened to my last post with questions to Richard Harrison.
I don't see it.

Comments inserted below.
--
Steve N, K,9;d, c. i My email has no u's.

"Walter Maxwell" wrote in message
news
On Fri, 05 Mar 2004 21:50:55 -0600, Cecil Moore


wrote:

wrote:
Non-dissipative resistance is not well accepted or understood by many

otherwise
well informed engineers, because it has had little or no (or even

incorrect)
treatment in EE courses.


On Sat. 06 Mar 2004 Cecil Moore wrote:

Yet the IEEE recognizes those two types of resistances with different

definitions.
Definition (A) talks about "dissipation or other permanent loss".

Definition (B)
simply says "The real part of impedance." Then a note: "Definitions (A)

and (B)
are *NOT* equivalent ..." (emphasis mine)

The resistance in a resistor satisfies definition (A). The characteristic
impedance of a transmission line satisfies definition (B).


What you said above is true, Cecil, but one more statement applies to

Definition
(B). Although Definitions (A) and (B) are not equivalent, Definition (B)

does
include the real part of the impedance of a dissipative resistor. The only

way
to tell which is which is to determine which develops heat.

I still maintain that many otherwise well qualified engineers not aware of
Definition (B), and therefore reject the concept of a resistance that

doesn't
dissipate power. And this applies to much more than the Zo of transmission
lines.



I consider myself very well qualified and have no problem with both
of these conditions and believe I understand them fully. (my post of
questions to Richard Harrison would show, if I could see it--wonder if I
didn't push the send button)

I can only say that I have never heard the term "non-disipative
resistance" either professionally or in the hobby. It is not taught. If I
had to say why, it is because it is a self-conflicting term. In my
nomenclature, all "resistance" dissipates power as heat. In other words,
resistance is what resistors have. Resistance can produce the real part of
an impedance, but the real part can come from other things.
In other situations such as the T-Line, there is a "real part" to
the impedance. The Engineer understands that this is due to a combinatin of
physical things, not only a resistor, so the term in question refers to
something that the Engineer does not need to discuss. When there is only
a real part (no reactance), then both are indistinguishable to the source --
so from the source's point of view, they are the same. In the bigger
picture, however, there is a difference -- heat vs. power going elsewhere.
However, I do not believe it is a good term (loss-less resistance) to use in
this case.
I would call it an unnecessary complication to add a new term of
"loss-less resistance" when you understand all of this. If you were to have
a term "loss-less real part", then I'd say you have a more accurate
technical term. Although, the Engineer (by this, I mean both me and those I
have discussed circuit concepts in school and professionally) knows what is
underdiscussion and what the impedance is and where it comes from, so a new
term is unnecessary.
I don't know if this helps, but it really seems to be adding a term
or name when it is not necessary.

So while the term may "work" for some people, I believe it is a
slight mis-use of the term "resistance".
When you first start talking about "loss-less resistance" to a
schooled Engineer, he'she gets the wrong idea as to just what you are
talking about since it is a conflict in terms.
--
Steve N, K,9;d, c. i My email has no u's.



And because there still remains many who believe the RF power amplifier

absorbs
and dissipates reflected power, I chose to try again to dispel that notion

in my
post in the 'max power theorem' thread.

Walt Maxwell, W2DU



  #88   Report Post  
Old March 8th 04, 09:29 PM
Steve Nosko
 
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"Steve Nosko" wrote in message
...
From: Richard Harrison )
Subject: Lossless Resistance?

ate: 2004-03-05 20:06:31 PST
Steve Nosko wrote:
"Power is calculated from "RMS" values of voltage and current."


Steve is correct! I apologize.


If you have a square wave of minimum peak to peak value of zero volts,
its maximum peak to peak value must be 1.414 x the d-c value. Then,
1.414 Vd-c x 1.414 Id-c = 2 Pd-c.


2 Pd-c x 1/2 t = Pd-c for an average.


Best regards, Richard Harrison, KB5WZI


Whew! Richard H.
For some reason, the above post does not show on my reader. I had to go
to Google to see what I was missing. After seeing your answer to my teaser
about voltage vs. power dB, I was really getting worried (about U) on this
one. You DO know. I think the thing here is that BOTH power and Current
are averaged by the chopper. I am, however, surprised that you did not have
a "gut feel" for that.

I just posted another short explanation of MY take on the term "loss-less
resistance".

I wonder why I am not seeing some posts..

There is another thread about the maximum power transfer theorm. This
thread was about the term "loss less resistance".
--
Steve N, K,9;d, c. i My email has no u's.


  #89   Report Post  
Old March 8th 04, 09:35 PM
Steve Nosko
 
Posts: n/a
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I wonder what happened to my last post with questions to Richard Harrison.
I don't see it. Boy! I'm not doing well at all on this Usenet thing
today.....

Comments inserted below.


--
Steve N, K,9;d, c. i My email has no u's.

"Walter Maxwell" wrote in message
news
On Fri, 05 Mar 2004 21:50:55 -0600, Cecil Moore


wrote:

wrote:
Non-dissipative resistance is not well accepted or understood by

many otherwise well informed engineers...no ...treatment in EE courses.

On Sat. 06 Mar 2004 Cecil Moore wrote:

Yet the IEEE recognizes those two types of resistances with different

definitions.
Definition (A) talks about "dissipation or other permanent loss".
Definition (B) simply says "The real part of impedance."
Then a note: "Definitions (A) and (B) are *NOT* equivalent ..." (emphasis

mine)

The resistance in a resistor satisfies definition (A). The characteristic
impedance of a transmission line satisfies definition (B).


What you said above is true, Cecil, but one more statement applies to

Definition B). Although Definitions (A) and (B) are not equivalent,
Definition (B) does include the real part of the impedance of a

dissipative resistor.
The only way to tell which is which is to determine which develops heat.

I still maintain that many otherwise well qualified engineers not aware of
Definition (B), and therefore reject the concept of a resistance that
doesn't dissipate power. And this applies to much more than the Zo of

transmission
lines.



I consider myself very well qualified and have no problem with both
of these conditions and believe I understand them fully. (my post of
questions to Richard Harrison would show, if I could see it--wonder if I
didn't push the send button)

I can only say that I have never heard the term "non-disipative
resistance" either professionally or in the hobby. It is not taught. If I
had to say why, it is because it is a self-conflicting term. In my
nomenclature, all "resistance" dissipates power as heat. In other words,
resistance is what resistors have. Resistance can produce the real part of
an impedance, but the real part can come from other things.
In other situations such as the T-Line, there is a "real part" to
the impedance. The Engineer understands that this is due to a combinatin of
physical things, not only a resistor, so the term in question refers to
something that the Engineer does not need to discuss. When there is only
a real part (no reactance), then both are indistinguishable to the source --
so from the source's point of view, they are the same. In the bigger
picture, however, there is a difference -- heat vs. power going elsewhere.
However, I do not believe it is a good term (loss-less resistance) to use in
this case.
I would call it an unnecessary complication to add a new term of
"loss-less resistance" when you understand all of this. If you were to have
a term "loss-less real part", then I'd say you have a more accurate
technical term. Although, the Engineer (by this, I mean both me and those I
have discussed circuit concepts in school and professionally) knows what is
underdiscussion and what the impedance is and where it comes from, so a new
term is unnecessary.
I don't know if this helps, but it really seems to be adding a term
or name when it is not necessary.

So while the term may "work" for some people, I believe it is a
slight mis-use of the term "resistance".
When you first start talking about "loss-less resistance" to a
schooled Engineer, he'she gets the wrong idea as to just what you are
talking about since it is a conflict in terms.
--
Steve N, K,9;d, c. i My email has no u's.



And because there still remains many who believe the RF power amplifier

absorbs
and dissipates reflected power, I chose to try again to dispel that notion

in my
post in the 'max power theorem' thread.

Walt Maxwell, W2DU




  #90   Report Post  
Old March 8th 04, 09:50 PM
Steve Nosko
 
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"Steve Nosko" wrote in message
...
I wonder what happened to my last post with questions to Richard Harrison.
I don't see it. Boy! I'm not doing well at all on this Usenet thing
today.....



BTW Richard H. No need to apologize. You made me go back and look closely
to make sure I had it correct. You saw the error AND you really do
understand -- that is the most important. I frequently have the fear that I
will speed through a calculation and get a response wrong. Excel is my
friend! Besides, I just finished pages and pages of these same calculations
spurred by Bob Schraders (error prone) Watt meter article in QST.

I hope I always sounded as though I was a discussion of concepts rather
than emotion. I was beginning to ask friends how to end the thread politely
with someone who has it wrong and just doesn't get it. I won't get
insulting (nudge, nudge, wink, wink), but I have this bone in my head which
makes me WANT to say "I know I'm right, I tried to help you understand so
you go prove it to yourself." without sounding insulting...
73,
--
Steve N, K,9;d, c. i My email has no u's.


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