Magnet Myths and Misconceptions

[MileHigh]

TK:

<<<
But that is in fact _exactly_ what is happening. Where do the electrons come from in the cathode ray? THEY COME OUT OF THE WIRE that connects the cathode to the rest of the circuit. They are pushed through the wire by voltage... that is, the electric field, that comes from _individual unit charges_ pushing each other apart. That is what voltage IS !!!
>>>

We are going to have to agree to disagree.  The electric field does _not_ come from individual unit charges pushing against each other when it comes from a source of induced EMF.  The individual electric charges are being pushed around by an external electric field.  The source of the energy is the EMF field and the charges are just the "agents" of the field.  Again, I am talking about electromotive force here.  The power grid is all EMF-based.

Here is a thought experiment:  You have a transformer secondary driving a load resistor.  There are three setups.  The first setup has the output of the secondary at 10 volts RMS driving a 10-ohm resistor.  The second setup has a secondary output of 100 VRMS driving a 100-ohm resistor.  The third setup has a secondary output of 1000 VRMS driving a 1000-ohm resistor.

So, the secondary wire and the resistor are neutral with no net charge.  In all three cases the current is one amp RMS.  Is there any difference in the electron density between the three setups because of charges pushing against each other?  The answer is no, if you put a bunch of high-end current probes at multiple places on each setup they would all give you exactly the same current waveform.  If you could measure the free electron density in the metal it would be the same in all three cases.  Electrons are not "pushing against each other to make the current flow."  Granted, in each setup there is a "sea" of valence electrons "jumping around."  The electrons in the high-voltage setup are not jumping around at any higher energy levels relative to their nuclei as compared to what is happening in the low-voltage setup.  But they are at a higher relative potential energy due to the fact that they are at the "tips" of the EMF field inside the long coil of wire.

Now of course the EMF is happening inside the transformer, so what about the interconnect wires?  The conductive wire by definition prevents the existence of an electric field inside the wire.  But the fact that there is a low finite resistance in the wires means that there is a low level of EMF inside the wires also.  It's all in "harmony" - the coil, the interconnect wires, and the load resistor - they all have the "correct" amount of EMF/electric field strength so that the current flow is the same everywhere.  In that sense the electrons are not pushing against each other.  The EMF is everywhere in the circuit at just the "correct" level so that all is the electrons flow at the same rate.

MileHigh

[MileHigh]

Another thought experiment:  What if the three coils are not connected to their load resistors?  One more time, let's ignore any electron flow due to parasitic capacitance.  Let's assume that you can observe the three coils in any manner without having to worry about the high voltage.  Let's assume that you are simply not looking at the voltage.  Will the three coils look any different from one another when you examine them in other ways?  I say that they won't, they will all look the same.

And just a reminder, all of this discussion is based on voltage induction, EMF.  I am not considering static electricity.  For static electricity, electron density does come into play.   I agree that in both cases you can measure voltage and the units are the same, it's the same voltage.  But there are fundamental differences with respect to the generation of EMF voltage and static-induced voltage.

Note that a capacitor bridges these two things.  An isolated capacitor has charged plates and that is an example of static electricity in action.  But when you connect a resistor across the capacitor, then I think that you can look at what happens in two ways that are mutually compatible.  You can say you have charges at high density pushing against each other and the charge repulsion will push the charges right through the resistor. Or you can say that you are back to EMF pushing current through the resistor because there is a strong electric field between the capacitor plates that also travels through the resistor.  When you connect a resistor across the capacitor plates, the electric field pushes the electrons through the resistor.

[mondrasek]

To summarize what I have come to understand from this discussion regarding an EF:  Voltage is a concentration of charge.  And since the negative unit charge carrier is the (free) electron, that means that Voltage is the result of a concentration of electrons.

Electrons are all the same (negative) charge and so want to repel each other.  So Voltage is very much like "pressure" as used in the mechanical analogy.  IE when you have a group of electrons that are freely spaced so as not to be too close to each other they do not repel each other very much and so there is very little or no Voltage.  But if those electrons are forced closer together their same charge fields are repelling each other.  The repulsive "force" between all of those electrons is Voltage.  And the "compressed" field of electrons are very much looking for a route to relieve the "pressure" that they are under.  And so if given the chance to return to an area of lower electron density (lower charge potential) they will go there.  And the closer they are together, the higher the Voltage, and the higher the Pressure, and therefor with more "gusto" they will go to that lower potential.

Can the word "gusto" above be replaced with the word "Energy?"

This explains to me how static electricity works.  For instance, on the collector of a VDG there is created a very large group of extra free electrons.  And so the surface of the collector also has a high Voltage.  But when you give that very large electron source on the collector a place to go where there is a lesser concentration of electrons (allow it to spark to somewhere, ie. ground out) all of those extra electrons will "jump" to that place of lower electron concentration under a high Voltage (pressure).  However, the group of electrons in the static electricity filed (on the collector of the VDG) have absolutely no backup electrons to flow as quickly and with so much Voltage (pressure) after that initial jump.  And so there is very little CURRENT (flow rate of the electrons) behind that discharge.

Okay?

M.

[Magluvin]

TK:

<<<
But that is in fact _exactly_ what is happening. Where do the electrons come from in the cathode ray? THEY COME OUT OF THE WIRE that connects the cathode to the rest of the circuit. They are pushed through the wire by voltage... that is, the electric field, that comes from _individual unit charges_ pushing each other apart. That is what voltage IS !!!
>>>

I had come to post just a quick pic of the coil and rotor, as Im looking for the proper hardware to mount to a pvc board base. And I read the statement above first and it has me reiterating my earlier post.....

In my mind, if the electron is the source of magnetic field effects, thinking on the lines of if the deflection coils in a cathode ray tube can attract or deflect an electron, then likewise the electrons in the beam must be a source of magnetic field distortion and orientaion, not just magnetic like iron where either pole N or S only pulls on them, so they must be so called magnets themselves.  Now when we read the quote above and take heed that it is true, then I have to say that electrons have a positive and negative side to them.  But these are not magnets as we know. They must be sort of like a cross section slice of say fine copper wire and the wire has DC current flowing through it.  So if we visualize the slice, say slice is as long as the width of the wire, for visualization, the field spins around the electron, and one flat side of the slice is positive and the other negative at all times.

So when we apply a dc source to the wire ends, the electrons in a straight piece of wire flow in one direction and the fields around the wire are also in the same orientation, then theoretically, I must conclude that the moving electrons in the wire are oriented + side facing the - source wire end, and the - side of the moving electron is facing the  + source end of the wire, therefore the magnetic orientation of each electrically affected electron in the wire are all the same. And that magnetic orientation can be reversed by switching the dc source on the wire in opposite polarity.

And it is possible that the electrons that dont move in the wire can also be finally moved from their strongholds by applying more voltage/charge at the source, disrupting their 'atomic' magnetic hold to their copper atom counterparts and that disruption in the electrons field could break it loose from the atom and become mobile, till it finds an empty seat with another atom that is missing and electron, if the source charge effects allow it to do so at the time.

So this is what I am adding to this thread as part of the discussion. To me, it doesnt sound far fetched really.   And if it is so, what experiments could possibly prove it?  Possibly measuring the field around a DC arc, showing that the electron passing through space has correct magnetic field orientation. But if you put a mag close to the side of the arc, do the N and S of the magnet both produce pull on the arc?

And possibly knowing that electrons have a positive and negative side to them, can that help us in any way? 

Just some things to think about.

Mags

[Magluvin]

pic was huge, so deleted it.  Hadnt posted a pic from this camera in a while, forgot to shrink.

Mags