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  • Thread starter Watson A.Name - 'Watt Sun'
  • Start date
R

Ratch

Jan 1, 1970
0
Tim Williams said:
Then please, by all means possible, go out and identify all books with
misnomers and incorrect information!!!

For what purpose?
The world needs you!

Some people maybe, but not the world.
Why are
you wasting your valuable time on Usenet?

Why does anyone participate here?
Hurry! While there is still
time!!!!

Take it easy, what's the rush?

Ratch
 
W

Watson A.Name - 'Watt Sun'

Jan 1, 1970
0
I agree with what you said above.


Yes, rho and R are proportional to each other, but that does not answer
the question I asked before (see the first paragraph above). How does L&M
define something as nonohmic when according to what they say, everything is
ohmic because it follows V=IR (which they say is Ohm's law).


I agree with that, but according to what you said about what L&M
writes, that never happens because all materials follow V=IR. Does L&M
mention
nonohmic materials? Ohm's law cannot be both V=IR and constant resistance
as current varies. Which one does L&M say it is? Ratch


Yes, according to what L&M says there is. Ratch

I think one has to look at the history of this. When Ohm's law was
defined, it's possible that non-ohmic conductors had not been
discovered. Hence everything that conducted obeyed Ohm's Law.

In that context, V=I*R would always apply. Hence at that time, it was
considered a part of Ohm's Law.

But later, things changed...

--
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###Got a Question about ELECTRONICS? Check HERE First:###
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goes directly to the trash unless you add NOSPAM in the
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Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
R

Ratch

Jan 1, 1970
0
Watson A.Name - 'Watt Sun' said:
I think one has to look at the history of this. When Ohm's law was
defined, it's possible that non-ohmic conductors had not been
discovered. Hence everything that conducted obeyed Ohm's Law.

In that context, V=I*R would always apply. Hence at that time, it was
considered a part of Ohm's Law.

But later, things changed...

Maybe.....I don't know. But that was then, this is now. Ratch
 
C

Chuck Harris

Jan 1, 1970
0
Ratch,

It comes down to a basic ability to read and understand
algebra!

If I tell you that y = m*x + b, and I tell you the variables
are x and y, do I really have to tell you that m and b are
constants?

If they are not constants, then I have to show that they are
dependent on x (or y). To do that I would write them as:

y = m(x) * x + b(x) Which changes the character of the

equation tremendously.

L&M told you that most, but not all materials have a current
density that is proportional to the electric field. Then,
they gave you the equation:

j = (1/rho) * E (9-16)

[not:

j = (1/rho(E)) * E or j = (1/rho(j)) * E ]

and told you it (9-16) was Ohm's Law.

Really, though, whether or not R is ohmic, is immaterial,
as long as you can describe R, the relationship we all
call Ohm's law works... it has to, because R is defined
to make it work.

If you want to argue this further, you really must cite
Georg S. Ohm's research work that shows he was only
interested in being deified over materials that are
purely ohmic, and you really must cite the individual, or
group that first coined the phrase "Ohm's Law" to see what
they meant by it. Citing Resnick, or L&M, or the tooth fairy
doesn't do it. None of them were involved in the deification
process, and as a result their arguments are pure speculation,
or conjecture.

The overwhelming body of evidence in the engineering literature
of the last 100+ years suggests that E = iR is properly named
as Ohm's law, just as most of us think it is.

-Chuck

Eq. (9-16) describes the current density in terms of the electric
field at a point in a conductor (Fig. 9-11). It is called Ohm's law.
materials that obey Ohm's law are usually called ohmic conductors. This
relation enables us to calculate the current flowing through a wire of
length L which is connected to two terminals - points between which
there is a potential difference V....]


Now here is where they crash. They first give equation (9-16) and call
it Ohm's law. Then they say that all materials that obey equation (9-16)
are ohmic. Well, all materials obey the resistivity equation (9-16).
Therefore by their reasoning, all materials are ohmic. They go on to say
that Ohm's law can be used to show the relationship between resisitivity,
current density, and electric field. That is certainly true for Equation
(9-16), but that is the resistivity equation and it stands on it own
independent of Ohm's law. The resistivity (9-16) is used to determine
whether a material has the Ohm's law property, but it is not Ohm's law per
se.

L&M could have said a bit more about what they meant about a material
not following Ohm's law; how they meant that a material that has a non
constant rho is non ohmic. However, I caught the meaning the first time
I read it, so it cannot have been too badly worded.


You were primed to understand it because of your exposure to this
discussion.

The trip from (9-16) to: V = RI is just a straight forward
rearrangement, and substitution. It still states the same thing as
(9-16). A material is non ohmic if R is not a constant.


I don't see L&M saying anything that corresponds to the last sentence
above. Again, the resistance equation V=IR can be used to determine if a
material has the Ohm's law property, but V=IR stands on its own and is not
Ohm's law per se. Look at
http://maxwell.byu.edu/~spencerr/websumm122/node50.html again. Ratch
 
C

Chuck Harris

Jan 1, 1970
0
And to further the anecdotal evidence:

With exception for one engineer that pronounced it jiga,
giga (pronounced like giggle) cycles per second is the only way
I heard it pronounced in the labs in the '60s. In the '70s when
Hertz became the fashion, it has always been "giga (pronounced like
giggle) hertz.

I have heard more than a few pronounce it "gigawiggles per second",
though.

I suspect that living in a southern US local that if we engineers
here started to use the "jiga" pronounciation with a regular basis, we
would end up being fired for using a racial slur. Kind of like
the D.C. mayor's aid that got fired for making the mistake of using
the word "niggardly" amoung the ignorant masses.

-Chuck
 
F

Franc Zabkar

Jan 1, 1970
0
As I said, it is derived from the international standards.

I doubt you will find any *international* standard where giga is
pronounced jiga. Unfortunately I can't find any non-US standard on the
Net, so I can't support my claim.
The old NBS (now NIST) publications, the ASME (American Society of
Mechanical Eng'rs), the U.S. Navy, and other publications show the
pronunciation as jiga.

All of these are US standards. You may as well suggest that speakers
of UK English revert to US spelling amendments such as "color" instead
of "colour", for example, or that the British alter their gallon to be
in line with the US measure, or that the world play football the
American way. Having said that, I believe simplicity should be the
primary determinant of language, which means that color makes more
sense than colour, but giga is better than jiga. Hopefully common
usage will eventually eliminate the latter.


- Franc Zabkar
 
F

Franc Zabkar

Jan 1, 1970
0
Jigahurts was the only way I heard Gigahertz pronounced back in the
'60s when I woekrd for a radio eng'g lab. That's not long after the
time when the prefizxes were adopted. Before that, it used to be
micromicrofarads instead of picofarads.

Somehow betwen then and now it got perverted to today's pronunciation.

I think the perversion was in the original pronunciation. English
already has thousands of inconsistencies and irregularities, primarily
as a result of Norman influence (IMO), so it makes no sense to
intentionally create new words with non-phonetic pronunciations and/or
spellings.


- Franc Zabkar
 
B

Bullwinkle Jones

Jan 1, 1970
0
Watson said:
Jigahurts was the only way I heard Gigahertz pronounced back in the
'60s when I woekrd for a radio eng'g lab. That's not long after the
time when the prefizxes were adopted. Before that, it used to be
micromicrofarads instead of picofarads.

Somehow betwen then and now it got perverted to today's pronunciation.

The only place I ever heard it pronounced jiga was in the Back To The Future
movies!
 
W

Watson A.Name - 'Watt Sun'

Jan 1, 1970
0
The only place I ever heard it pronounced jiga was in the Back To The Future
movies!

My dictionary, Webster's New Collegiate, shows both, but jiga is
first, and it says that the first is the preferred pronunciation.
Many dictionaries are like this, some don't even have the second.
Perhaps the people in the movie had the simple foresight to simply
consult a dictionary when they made the movie.

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
R

Ratch

Jan 1, 1970
0
Chuck Harris said:
Ratch,

It comes down to a basic ability to read and understand
algebra!

If I tell you that y = m*x + b, and I tell you the variables
are x and y, do I really have to tell you that m and b are
constants?

If they are not constants, then I have to show that they are
dependent on x (or y). To do that I would write them as:

y = m(x) * x + b(x) Which changes the character of the

equation tremendously.

L&M told you that most, but not all materials have a current
density that is proportional to the electric field. Then,
they gave you the equation:

j = (1/rho) * E (9-16)

[not:

j = (1/rho(E)) * E or j = (1/rho(j)) * E ]

and told you it (9-16) was Ohm's Law.

Really, though, whether or not R is ohmic, is immaterial,
as long as you can describe R, the relationship we all
call Ohm's law works... it has to, because R is defined
to make it work.

I think you are refering to the "relationship" as being the equation.
That is not Ohm's law, the linearity property is.
If you want to argue this further, you really must cite
Georg S. Ohm's research work that shows he was only
interested in being deified over materials that are
purely ohmic, and you really must cite the individual, or
group that first coined the phrase "Ohm's Law" to see what
they meant by it.

And how does anyone do that? How would I track something like that
down and interview folks that have been dead for such a long time? One can
assume that it is called Ohm's law because he was the one that proposed that
current is proportional to voltage for many materials.
Citing Resnick, or L&M, or the tooth fairy
doesn't do it. None of them were involved in the deification
process, and as a result their arguments are pure speculation,
or conjecture.

I hope you mean giving credit where credit is due as being the
"deification process" Resnick and L&M are experts in their field, and their
opinions should be taken into account and evaluated. You can argue that
they did not explain things well enough, or are mistaken, or even careless.
But you cannot realistically say their writtings on this subject are
imaginary, like the tooth fairy.
The overwhelming body of evidence in the engineering literature
of the last 100+ years suggests that E = iR is properly named
as Ohm's law, just as most of us think it is.

I think the overwhelming evidence is that resistance formula has been
wrongly named for a long time now. Ratch
-Chuck

Eq. (9-16) describes the current density in terms of the electric
field at a point in a conductor (Fig. 9-11). It is called Ohm's law.
materials that obey Ohm's law are usually called ohmic conductors. This
relation enables us to calculate the current flowing through a wire of
length L which is connected to two terminals - points between which
there is a potential difference V....]


Now here is where they crash. They first give equation (9-16) and call
it Ohm's law. Then they say that all materials that obey equation (9-16)
are ohmic. Well, all materials obey the resistivity equation (9-16).
Therefore by their reasoning, all materials are ohmic. They go on to say
that Ohm's law can be used to show the relationship between resisitivity,
current density, and electric field. That is certainly true for Equation
(9-16), but that is the resistivity equation and it stands on it own
independent of Ohm's law. The resistivity (9-16) is used to determine
whether a material has the Ohm's law property, but it is not Ohm's law per
se.

L&M could have said a bit more about what they meant about a material
not following Ohm's law; how they meant that a material that has a non
constant rho is non ohmic. However, I caught the meaning the first time
I read it, so it cannot have been too badly worded.


You were primed to understand it because of your exposure to this
discussion.

The trip from (9-16) to: V = RI is just a straight forward
rearrangement, and substitution. It still states the same thing as
(9-16). A material is non ohmic if R is not a constant.


I don't see L&M saying anything that corresponds to the last sentence
above. Again, the resistance equation V=IR can be used to determine if a
material has the Ohm's law property, but V=IR stands on its own and is not
Ohm's law per se. Look at
http://maxwell.byu.edu/~spencerr/websumm122/node50.html again. Ratch
 
B

Bob Masta

Jan 1, 1970
0
The only place I ever heard it pronounced jiga was in the Back To The Future
movies!

I first heard the jiga pronounciation from a former Tektronix
scope front-end designer. (Hi, Frank!) My impression was
that this was standard pronounciation there.


Bob Masta
tech(AT)daqarta(DOT)com

D A Q A R T A
Data AcQuisition And Real-Time Analysis
Shareware from Interstellar Research
www.daqarta.com
 
B

buck rojerz

Jan 1, 1970
0
After following this 'wild' thread, it seems as though the main argument
revolves around this "Ohmic" and "non-ohmic" thing. Can any one of you
tell this old technician, just what "non-ohmic" is?

Without knowing what your explination is, one might assume non-ohmic as
being a material with no resistance. If that is the case, the only non-
ohmic substance would be super-conductors, but somehow it sounds like
that's not what you are meaning.

So, please explain what "non-ohmic" means to you. For the life of me I
can't figure out what you mean. In thirty years, I have never heard the
term.

buck
 
R

Ratch

Jan 1, 1970
0
buck rojerz said:
After following this 'wild' thread, it seems as though the main argument
revolves around this "Ohmic" and "non-ohmic" thing. Can any one of you
tell this old technician, just what "non-ohmic" is?

Without knowing what your explination is, one might assume non-ohmic as
being a material with no resistance. If that is the case, the only non-
ohmic substance would be super-conductors, but somehow it sounds like
that's not what you are meaning.

So, please explain what "non-ohmic" means to you. For the life of me I
can't figure out what you mean. In thirty years, I have never heard the
term.

Sure. Read this short link that was posted by me earlier. You will
find it enlightening. Ratch
http://www.launc.tased.edu.au/online/sciences/PhysSci/done/electric/resistnc/Resistance.htm
 
F

Franc Zabkar

Jan 1, 1970
0
How do the Greeks pronounce "gigas"? The "jig-a" pronounciation
for giga seems to be in more-or-less in keeping with "gigantic".

Even more consistent would be "j-eye-ga". ;-)


- Franc Zabkar
 
R

Ratch

Jan 1, 1970
0
buck rojerz said:
After following this 'wild' thread, it seems as though the main argument
revolves around this "Ohmic" and "non-ohmic" thing. Can any one of you
tell this old technician, just what "non-ohmic" is?

Without knowing what your explination is, one might assume non-ohmic as
being a material with no resistance. If that is the case, the only non-
ohmic substance would be super-conductors, but somehow it sounds like
that's not what you are meaning.

So, please explain what "non-ohmic" means to you. For the life of me I
can't figure out what you mean. In thirty years, I have never heard the
term.

Sure. Read this short link that was posted by me earlier. You will
find it enlightening. Ratch
http://www.launc.tased.edu.au/online/sciences/PhysSci/done/electric/resistnc/Resistance.htm
 
C

Clifton T. Sharp Jr.

Jan 1, 1970
0
Watson said:
Generally speaking, the first listing in the dictionary is the
preferred pronunciation.

Careful about that. I ran into one dictionary whose front section gave
an extremely convoluted set of rules for deciding which of multiple
pronunciations was the preferred one.
 
B

buck rojerz

Jan 1, 1970
0
After following this 'wild' thread, it seems as though the main argument
revolves around this "Ohmic" and "non-ohmic" thing. Can any one of you
tell this old technician, just what "non-ohmic" is?

Without knowing what your explination is, one might assume non-ohmic as
being a material with no resistance. If that is the case, the only non-
ohmic substance would be super-conductors, but somehow it sounds like
that's not what you are meaning.

So, please explain what "non-ohmic" means to you. For the life of me I
can't figure out what you mean. In thirty years, I have never heard the
term.

buck

Man, did that ever bring this thread to a sudden stop.
What? Nobody knows?
 
S

Sir Charles W. Shults III

Jan 1, 1970
0
Well, for one thing, a couple of us have explained what non-ohmic is.
Repeating myself brings a lot of my chats to a sudden halt. Here are some
examples- incandescent lamp filament, LED, transistor.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip
 
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