Electron flow

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Re: Electron flow

Originally posted by rattus:
[QB] I don't think this question has a simple answer--maybe no answer at all. There is a phenomenon called "force on a moving charge".

Rattus,
This phenomennon called "force on a moving charge" is what I'm calling
"real movement of energy" It sure is an interesting Phenomenon.
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Re: Electron flow

Sparks, you can call it what you wish, but no one else will know what you are talking about. "Force on a moving charge" is the very desriptive term found in the physics and engineering books. No point in calling it anything else.
 
Re: Electron flow

Originally posted by sparks1: Why do we use the term "current flow" when in fact it really doesn't flow very far at all?
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Can we PLEASE PLEASE PLEASE stop saying that? You need to understand that current is the motion of charge, and charge propagates down the wire at nearly the speed of light. For all practical purposes, we can say that individual electrons will themselves race down the wire at nearly the speed of light. It does not matter if one electron goes the distance, or whether it works more like a relay race, in which one electron will ?pass the baton? to another, and then stop running. The fact is that charge continues to move down the wire, and it travels great distances at great speeds. Again, for all practical purposes, we can say that in every half-cycle of an AC signal, each moving electron (some stay attached to their host atom) will travel 8 million feet!
The "real movement of energy" is created by the striking of the valence electrons.
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No it?s not. The transfer of energy from the source to the electrons, and from the electrons first to the wire and then to the load, is not by physical contact (striking) of an electron against another body. The energy transfer occurs through the interaction of charge and electro-magnetic fields.
 
Re: Electron flow

I was curious so I checked it out and got 8.184 million feet. That's what I figured you did Charlie. :D

Sparks1, think of the ping pong balls in a hose or a tube analogy for this.

If you put ball bearings in a tube you can take a hammer and drive a nail with the ball bearings between the hammer and nail. How much did the ball bearings move?

Edit: The energy was transmitted across the row of ball bearings while the ball bearings hardly moved.

[ February 24, 2005, 11:59 AM: Message edited by: physis ]
 
Re: Electron flow

I think it's around 95%. That would come out to 7.7748 million feet per half cycle.

Edit: I used the wrong units.

[ February 24, 2005, 12:28 PM: Message edited by: physis ]
 
Re: Electron flow

Bryan,

While 1% of the speed of light compared to walking is a huge speed, compared to the speed of light it is nearly imperceptable.

If I decrease the speed of my car by 1% (say from 60 mph to 59.4 mph) I will be hard pressed to know it.
 
Re: Electron flow

But if you're hanging around with a bunch of photons and one guy starts going 99%, you'll be saying, where'd the other guy go? :D
 
Re: Electron flow

The transfer of energy from the source to the electrons, and from the electrons first to the wire and then to the load, is not by physical contact (striking) of an electron against another body.
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Charlie B, most texts and articles describe heat produced by current as resulting from collisions between the moving electrons and the atoms of the conductor material.

How do you respond to this quote?
"The atom-electron collisions in a wire can be assumed to be an effective internal friction.
The energy transferred from the electron to the atoms of the metal during collisions causes an increase in the temperature of the conductor."

Here is a link to the paper.
Current and Resistance

Ed
 
Re: Electron flow

Sam,

But the relative motion difference is still the same as from 60 to 59.4.

[ February 24, 2005, 12:49 PM: Message edited by: al hildenbrand ]
 
Re: Electron flow

Ed, electron collision is a simplification, nothing wrong with that. But you're not gonna get to electrons to touch each other outside of a neutron star or black hole.

Al, photons are snobs, if you can't keep up, they don't know you. :D
 
Re: Electron flow

The Newtonian banging together of objects, while helping to convey the notion of the concepts, ultimately has to be tempered with other paradigms.

At the quantum level, the electric force is carried by photons. Driving a nail with ball bearings in a tube elegantly shows the force moving while the bearings remain relatively stationary. Now think of the physical volume of the ball bearing as the volume of void that has an atom at its center and some other particals scattered extremely thinly throughout. The electric force travels through this void on force carrier photons as the blow of a hammer's force passes through a "solid" ball bearing.
 
Re: Electron flow

Let's get real here. A signal in a coax line propagates at about 2/3 the speed of light, that is about 1 foot in 1.5 nanoseconds. This from memory, someone check me out. But the typical wire twister is not at all concerned with this, nor should he be. He should be concerned with doing a professional job, according to code, and making a decent profit for himself.

I do think that the electician should know that an Ampere of current means a charge flow of 1 Coulomb/second and that it takes a lot of electrons to provide that one Coulomb. I think it is confusing to pretend that electrons race around the wire at the speed of light when there are simple analogies which describe the actual charge flow mechanism.

Also, the wire twister is not concerned about the mechanism of heat generation in a wire or resistance. He should however understand Ohm's law and the power formulas. And I think that the collision analogy is plausible because we do know that changing energy levels of electrons radiate energy, e.g., in a light emitting diode.

Some of these things are like the fundamental propositions in geometry. In other words, this is the way it is, and the phenomena may be described mathematically, but no one can explain it fully.
 
Re: Electron flow

Rattus,

I think a wire twister who wants to know more than twisting wire should be assisted in understanding to whatever depth he desires. :)
 
Re: Electron flow

Sam and Al,

Absolutely! But, few wire twisters do try to understand the theory to this depth. For those who do, more power to them, and I am more than happy to assist as best I can.

Now, let me say that my ancestors were farmers and tradesmen, and I have the utmost respect for them and their craft and for their modern day counterparts. My favorite example is the tape and bed man who walks around on stilts and does in minutes what I would take hours to do. Furthermore, he does a professional job, and I make a mess.

In other trades, one can see what he is doing, but the electrician has to work with things unseen and dangerous. It takes a different breed of cat to be a good electrician in my opinion.
 
Re: Electron flow

While my wire nut connections are Newtonian. . .so massive as to exhibit no discernable quantum effects. . .the popular media offers me occasional productions investigating the non-Newtonian universe.

Just yesterday I noted that Chicago Fermilab has commenced firing a beam of neutrinos through the Earth's crust, under the entire State of Wisconsin and Lake Superior, to a 6,000 ton collector built in a high energy physics lab ? mile down in the abandoned Soudan Iron Mine.

The very medium we are using to have this collective conversation through is riddled with non-Newtonian physics.

Our individual social milieu includes an ever increasing component that is the stuff of science fiction to an early 20th century "wire bender".

Because, as rattus so aptly states
the electrician has to work with things unseen and dangerous
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we correctly start with simple models to explain and teach how to avoid danger. But the simple model, in the presence of today's popular notions of quantum reality, begs deeper explanations.
 
Re: Electron flow

I'll give you all my vote!
The more we all talk about this subject the little bit more we'll all learn.
Yes, Rattus I should use the correct term "Force charge". Now do you see, I've just learned something new!

"The energy in a circuit "is" the energy of the electromagnetic field".

The Kinetic energy of electrons really doesn't matter very much.

[ February 24, 2005, 03:21 PM: Message edited by: sparks1 ]
 
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