# Elementary question - what makes the current flow?

W

#### Who Am I?

Jan 1, 1970
0
There are many equations to describe what happens whenever
it does happen, but why does the current flow in the first place?

I used to think that it was electrostatic pressure caused by all
the electrons being bunched up against each other and so
pushing them apart, but someone said to me recently, that
the electrons are merely being dragged along by the travelling
electric wave.

So, why does the current start flowing in the first place
(when there is no wave to drag them along)?

And why does it keep flowing?

B

#### Bill

Jan 1, 1970
0
There are many equations to describe what happens whenever
it does happen, but why does the current flow in the first place?

I used to think that it was electrostatic pressure caused by all
the electrons being bunched up against each other and so
pushing them apart, but someone said to me recently, that
the electrons are merely being dragged along by the travelling
electric wave.

So, why does the current start flowing in the first place
(when there is no wave to drag them along)?

And why does it keep flowing?

I think the "ions" are migrating in one case...
http://en.wikipedia.org/wiki/Galvanic_corrosion

A

#### Archimedes' Lever

Jan 1, 1970
0
Neglecting some detail, there is a potential difference between the one
side (the hot side) of the power source and the neutral side of the
circuit. This means that positive electric charge will be in a lower
energy state if it at the negative side. It is like a ball being more
stable at the bottom of a slope because it has less potential energy
there.

Thus with a potential across an appliance, current will flow. EEs say
there is an electric field pushing current through the appliance. The
same is true of the connecting wires. There is some push of the current
through the wires to enable flow against the electrical resistance. This
is small compared the the push through the appliance where work is being
done whether it is heating or driving a motor.

To reiterate, Electric field pushes charge. You want to push it hard
where you want work to be done. Electrical push is potential difference
or voltage.

Bill

Current is the same at any point along the circuit, so the 'push' is
the same everywhere. Where "work" is done, the push results in heat, but
the push is the same, nonetheless. Where there is no work, as is the
case with an ideal conductor, there is no heat, as it pushes right
through easily, but the push is the same nonetheless.

In a conductor the push is supposed to be "easy" on the conductor.
That's why we use them. That is also why they have limits to how much
one can push through them. Even they begin to heat at some point, which
proves that they are not "an ideal conductor", but we have managed to get
pretty damned close.

So you are wrong., Bill. You may have had an idea for an analogy, but
it fell on its face. Try again. The push is the same everywhere. The
thing that differs is the work that gets done on all the little parts
along the way. The load or work site is one part. Each piece of wire is
another. Each item has their own little resistance to present to the
power source. The whole 'circuit' is made up of these pieces.

The push is the same, the "work" done along the way at each 'piece' is
what differs.

R

#### Rich.

Jan 1, 1970
0
Who Am I? said:
There are many equations to describe what happens whenever
it does happen, but why does the current flow in the first place?

I used to think that it was electrostatic pressure caused by all
the electrons being bunched up against each other and so
pushing them apart, but someone said to me recently, that
the electrons are merely being dragged along by the travelling
electric wave.

So, why does the current start flowing in the first place
(when there is no wave to drag them along)?

And why does it keep flowing?

Electricity is the transfer of electrons from one atom to the next,
traveling in the same direction.

A

#### Archimedes' Lever

Jan 1, 1970
0
And then there is "hole flow"...

A pretty big one flowed between your ears.

G

#### Guest

Jan 1, 1970
0
Bill said:
-----------------------------------
Rather than consider electrons going one way filling holes which ,as a
result, are going the other way, there is an approach, when considering the
overall effect rather than the particle/non-particle motion (ignoring
waves) use the classical current definition as in the direction of "positive
charge" flow and stick with a single convention and eliminates a lot of
guessing- "do I stick a negative sign in here or not?"- particularly
problematic with AC.

A

#### Archimedes' Lever

Jan 1, 1970
0
-----------------------------------
Rather than consider electrons going one way filling holes which ,as a
result, are going the other way, there is an approach, when considering the
overall effect rather than the particle/non-particle motion (ignoring
waves) use the classical current definition as in the direction of "positive
charge" flow and stick with a single convention and eliminates a lot of
guessing- "do I stick a negative sign in here or not?"- particularly
problematic with AC.

Which, of course, makes it easier to relate to any work product involved.

W

#### Who Am I?

Jan 1, 1970
0
Salmon Egg said:
Neglecting some detail, there is a potential difference between the one
side (the hot side) of the power source and the neutral side of the
circuit. This means that positive electric charge will be in a lower
energy state if it at the negative side. It is like a ball being more
stable at the bottom of a slope because it has less potential energy
there.
Thus with a potential across an appliance, current will flow. EEs say
there is an electric field pushing current through the appliance. The
same is true of the connecting wires. There is some push of the current
through the wires to enable flow against the electrical resistance. This
is small compared the the push through the appliance where work is being
done whether it is heating or driving a motor.
To reiterate, Electric field pushes charge. You want to push it hard
where you want work to be done. Electrical push is potential difference
or voltage.

Thanks, your vote lies with the electrostatic pressure explanation; the
greater the packing density of electrons, the greater the electric field.

A

#### Archimedes' Lever

Jan 1, 1970
0
Thanks, your vote lies with the electrostatic pressure explanation; the
greater the packing density of electrons, the greater the electric field.
"Packing density"? Who are you? You're an idiot, that's who.

T

Jan 1, 1970
0
God! God is very busy and very powerful. God makes the trees leave in
the Spring and at the same time creates stars billions of light years
away. God never finished creation and we are still in process. That
is what evolution is, God's tweaking us to completion. All the motors
and circuits are under his constant control, for without God's might
there would be no current flow whatsoever.
Additionally, God is infinite. God has always been and will always
be. There is no beginning of time and no end because time and space
are continuous.
Wait until you learn about what is in store for us. For all around us
is the secret of gravity. We will find that secret and then a new
world will be at our disposal. Yes, there are many more processes
that we have yet to discover. God has created them and they are there
just waiting for us to find them.

Doo doo, doo doo...

Doo doo, doo doo... (Twilight Zone inflection)

W

#### Who Am I?

Jan 1, 1970
0
There are many equations to describe what happens whenever
it does happen, but why does the current flow in the first place?

I used to think that it was electrostatic pressure caused by all
the electrons being bunched up against each other and so
pushing them apart, but someone said to me recently, that
the electrons are merely being dragged along by the travelling
electric wave.

So, why does the current start flowing in the first place
(when there is no wave to drag them along)?

And why does it keep flowing?

.... < Palpable bollocks deleted > ...

You are quite wrong in your assumed assessment of me.

I completed an electronics degree over 20 years ago, and looking at
the shelf of textbooks I mused that if I didn't get around to reading them
again soon, I never would.

So, out of interest, I started reading them all again, and came to the
conclusion
that there was a great deal left unsaid and unexplained, even at the degree
level.

I also accept that despite my level of education, that I do not know
everything,
and in pursuit of the truth, am prepared to admit my limitations in order
to achieve intellectual satisfaction.

I perceive now, that at whatever level one studies electricity, from the age
of
11 years upwards, that one is presented with a series of paradigms, none
of which are complete, and all of which are misleading to some extent.

Even at the level of Maxwell's Equations, electric charge is presented as
point
function akin to mass, whereas the physicist might claim that the electron
is
not a point, but a wave function.

So, as a part of my extended revision, I awakened the paradigm of electrons
being bunched together against their mutual repulsive forces (the "packing
density" sneered at in another post by a further example of rampant
childhood)
and the electric current (and I am definitely discussing electrons and not
positive
ions) being caused by that pressure from the electric field.

However, in discussion with a fellow radio ham (for such am I also) he
suggested
that the current flow in a waveguide is not caused by the mutually repulsive
electric field between electrons, but that the electrons are carried along
under the
influence of a travelling e-m field and that the original emf that set the
wave in motion
is no longer relevant.

Hence the question that I posed.

Perhaps I was in error in posing a question about elementary matters in
language
that was itself more redolent of the elementary school and so attracted
from one or two who should perhaps still be confined to the classrooms of
that elementary school? If so, then I apologise, but I'm still interested in
the
elementary mechanisms of electric current, but from a perspective of one who
has experience of much more in-depth paradigms.

B

#### Bungalow Bill

Jan 1, 1970
0
... < Palpable bollocks deleted > ...

You are quite wrong in your assumed assessment of me.

I completed an electronics degree over 20 years ago, and looking at
the shelf of textbooks I mused that if I didn't get around to reading them
again soon, I never would.

STUDYING, which it is obvious never happened.

B

#### Bungalow Bill

Jan 1, 1970
0
So, out of interest, I started reading them all again, and came to the
conclusion
that there was a great deal left unsaid and unexplained, even at the degree
level.

Bwuahahahahahahahahaha!

W

#### Who Am I?

Jan 1, 1970
0
Bungalow Bill said:
STUDYING, which it is obvious never happened.

Yet another inhabitant from the elementary school seems to have escaped

W

#### Who Am I?

Jan 1, 1970
0
Bungalow Bill said:
Bwuahahahahahahahahaha!

I pity you because either you are annoyed that you don't know
the answer, or else you are incapable of partaking in a public debate
in a seemly fashion.

<PLONK!>

C

#### Corbomite Carrie

Jan 1, 1970
0
Yet another inhabitant from the elementary school seems to have escaped

Yeah... YOU, ya dumbfucktard.

G

#### GoldIntermetallicEmbrittlement

Jan 1, 1970
0
I pity you because either you are annoyed that you don't know

The answer to what, you stupid ****? There was no valid question
posed.

or else you are incapable of partaking in a public debate
in a seemly fashion.

There was no debate either, idiot!

Unless you want to debate the fact that I say that you learned
absolutely NOTHING when you took the electronics course.

You're an even bigger retard than I originally estimated.

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