Elementary question - what makes the current flow?

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?

"Who Am I?" wrote in message
> 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

On Sun, 07 Mar 2010 10:30:24 -0800, Salmon Egg <(E-Mail Removed)>
wrote:

>In article <hmvpgp$h61$(E-Mail Removed)>,
> "Who Am I?" <(E-Mail Removed)> wrote:
>
>> 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?
>
>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.

"Who Am I?" <(E-Mail Removed)> wrote in message
news:hmvpgp$h61$(E-Mail Removed)...
> 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.

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

And then there is "hole flow"...
http://everything2.com/title/hole+flow

On Sun, 7 Mar 2010 18:05:03 -0800, "Bill" <(E-Mail Removed)> wrote:

>>
>> Electricity is the transfer of electrons from one atom to the next,
>> traveling in the same direction.
>
>And then there is "hole flow"...
>http://everything2.com/title/hole+flow

That's still electrons.

On Sun, 7 Mar 2010 18:05:03 -0800, "Bill" <(E-Mail Removed)>
wrote:

>>
>> Electricity is the transfer of electrons from one atom to the next,
>> traveling in the same direction.
>
>And then there is "hole flow"...

A pretty big one flowed between your ears.

"Bill" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>>
>> Electricity is the transfer of electrons from one atom to the next,
>> traveling in the same direction.
>
> And then there is "hole flow"...
> http://everything2.com/title/hole+flow
>
-----------------------------------
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.

--
-----
Don Kelly
cross out to reply

On Sun, 7 Mar 2010 19:49:58 -0800, <(E-Mail Removed)> wrote:

>"Bill" <(E-Mail Removed)> wrote in message
>news:(E-Mail Removed)...
>>>
>>> Electricity is the transfer of electrons from one atom to the next,
>>> traveling in the same direction.
>>
>> And then there is "hole flow"...
>> http://everything2.com/title/hole+flow
>>
>-----------------------------------
>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.

"Salmon Egg" <(E-Mail Removed)> wrote in message
news:SalmonEgg-(E-Mail Removed)...
> In article <hmvpgp$h61$(E-Mail Removed)>,
> "Who Am I?" <(E-Mail Removed)> wrote:
>> 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?
> 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.