A question about resistance

[jibbguy]

Adam,

Yer welcome. 

There could certainly be differing effects if AC frequency is involved (or single-polarity-going pulses of varying F), especially if Capacitance and/or Induction were factors in the circuit too (that is the "Z" Impedance factor, and includes Phase, and is highly dependent on Frequency and even waveform shape). But in "straight" (DC) Resistance.. "Nope", no difference could be detected in R between materials or sizes with the same Ohm rating (other than that caused by over-heating if the conductor / resistor were too small for the current load).

What you might see though, is significant differences in magnetic field strength between different conductors (for instance, a thick flat bar verses a twisted pair of wires but both having the same DC Ohm value.. The bar could create a fairly large magnetic field where the twisted wires would have hardly any). This magnetic field generated by current passing through the conductor could possibly affect other nearby components, and give the illusion of a different DC Resistance or otherwise cause "problems".

I remember this happening once with a current shunt (metal bar with like 0.3 Ohm R, used to read the V across it to calculate current); it gave off a magnetic field when at higher current loads that messed with a nearby little choke coil and thereby increased "loose capacitance" that in turn stopped an LM gate in an entirely different logic branch of the circuit from working reliably, lol. These kinda things are the main reason you see so many "Revisions" listed on schematics (well, next to not being able to source a certain component any more which is the top reason). 

And "Conductance" is a different story than "Resistance", since there are differing qualities for every material and grade and it is also frequency-dependent with some materials.  Also, very low ambient temperatures could have an effect on different materials' R rating. But in the end, there should always be a definite and repeatable "Ohms" value for the DC Resistance of the material at any one set point in time. Lol, and be glad for this as it is about the only Constant that we can rely on

[nitinnun]

don't use copper wire.

wire is an imperfect implementation compromise,
from the 1800's.

Tesla must only have used it,
because at the time,
they lacked the machining quality to do better.


use a long,
wide,
flat strip of copper foil.

such as copper fletching,
from the hardware store.
even if you have to cut it into smaller strips.


solder the copper foils sharp edges,
with a thin layer of soldering material.
to "smooth" the edges.

this should prevent corona discharge,
of the amperage.


then cover the copper foil,
with the insulation of your choice.
such as sandwiching it between 2 slabs of cardboard,
which are taped and/or zip tied together.

or use 2 or 3 layers of trash bag,
if you need flexible insulation

(some people use trash bag,
to make super capacitors,
for their Tesla Coils.
so be confident, that it works)


this "smooth edged copper foil",
would in theory have a superior current bandwidth,
on both its surfaces.
with the thin inner atoms,
being mostly unused anyway.


if you coiled several feet of smooth foil,
into a ring shaped coil,
it might create an interesting magnetic field.


of course copper wire,
still has its advantages.

(if you have the money and machining abilities,
to get it).

(or you don't mind 90% of the copper inside the wire,
wasting space,
wasting material,
and wasting money).


just as the smoothed edge foil,
has its advantages.

(it should be much tougher against physical damage.
being much harder to cause discontinuity in it,
through bending/abuse).

(ironically, i think the foil is cheaper,
than an equal amount of copper wire.
because the foil must be easier to smelt,
without critical imperfections,
than the wire).

[spiralout]

@jib,

wow,  thanks a million for your time and effort
my current knowledge of the technical terms
doesn't allow me to understand all of it right now,
but I'll get there... 

@nitinnun,

Thanks man, some good stuff to chew on...


Adam

[Philip Hardcastle]

It strikes me that if the wire be from fat to thin,
and the electrons doth flow towards the narrow.
Then there should be an electron gas pressure within
that upon the increase of diameter, as though left fallow,
would cause a drop in temperature, or is that shallow?

[spiralout]

@Philip,

Not shallow but profound,
I really like the way it sounds.
For energy to move around,
Potential difference should be found,

Now the cone he is quit strange,
In the way that he's arranged,
In his design there is a seed,
Potential difference he might feed.

LOL, I'm on a role!

@All

I just saw a movie which had a short
explanation about the dynamics of tornado
creation. Simply put, cold front encounters
hot front and the potential difference between
them creates an elongated cone of spinning
energy. Beautiful things to watch, tornadoes.

Anyway, that made me think, is there a way
to reverse the process? I'm talking small scales,
of course. Can we somehow imitate the phenomena?

These are some thoughts of the top of my head,
if it resonates with someone, please let me know
if there is some merit to it.


Cheers,

Adam