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?
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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
--
An old man would be better off never having been born.

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wrote:

Thanks, your vote lies with the electrostatic pressure explanation; the greater the packing density of electrons, the greater the electric field.
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Electricity is the transfer of electrons from one atom to the next, traveling in the same direction.
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Is a beam of protons or deuterons a flow of current even without an electron in the vicinity?
Saying that electricity is a transfer of electrons has caused more misconception than clarity over the years. The nature of the charge is irrelevant. Charge is electricity. Flow of charge is electric current,
Sometimes pedantic accuracy is useful. Explaining electricity is one of those times.
Bill
--
An old man would be better off never having been born.

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That's still electrons.
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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.
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On Mon, 8 Mar 2010 21:02:14 -0800 (PST), electrician

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

... < 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 comments 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.
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On Tue, 9 Mar 2010 08:56:50 -0000, "Who Am I?"

Reading? Novels are for reading. Textbooks meant for learning are for STUDYING, which it is obvious never happened.
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wrote:

Yet another inhabitant from the elementary school seems to have escaped
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On Tue, 9 Mar 2010 13:50:22 -0000, "Who Am I?"

Yeah... YOU, ya dumbfucktard.
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Who Am I? wrote:

--
Greed is the root of all eBay.

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On Tue, 9 Mar 2010 08:56:50 -0000, "Who Am I?"

Bwuahahahahahahahahaha!
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wrote:

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!>
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On Tue, 9 Mar 2010 14:59:06 -0000, "Who Am I?"

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

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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I too completed my Mathematics degree many years ago. I used to think Physics was a revelation of how God created this universe until I learned that all laws of physics are mere approximations, and that is a bout the best we can do. God did not used such rigid structures in his design but allowed for a multitude of variables and yet the processes still work for us and him. The more I learn about his infinite power the more I realize that we with all our knowledge know about as much as one grain of sand on a planet of beaches. Look out onto the many stars at night and one begins to realize just how small we are. What makes current flow? GOD!
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wrote:

You would be better advised to seek the attention that you seek from a psychiatrist and not from this group. It is not unheard of for young children to have an imaginary friend, but to have such a belief in adulthood is a very clear indication of mental illness.
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Any person that cannot believe in God surely is suffering from delusions placed in their head by a misconception that Man's knowledge is divine. It is like thinking the sun rotates around the earth. So I presume, you have seen an electron and know why current flows. I presume you think cause and effect, and an end and beginning are part of all processes. I presume that your thinking is inside the box created by empiricists and you simply cannot crawl out from under the weight of years of rational concrete thinking. You are programmed.
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On Wed, 10 Mar 2010 10:08:09 -0800 (PST), electrician

No. Essentially, YOU are an idiot. And every response you give supports the claim.
Empiricize that, dipshit.
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