How Electricity Actually Works

@deludedaudiophile

Thanks for the response.

Your comments are on par with things I have read since 2010 on the subject matter.

I read nothing in your post that differed from what the Late Ralph Morrison, Herman (agon member), the Late almarg (agon member), William J Beaty ( Misconceptions Spread By K-6 Textbooks: "Electricity"), Ian M. Sefton (School of Physics, The University of Sydney, Australia), and countless others I consider authorities on the subject matter.

 

I knew better when I said the load consumes energy. It really doesn’t. Energy is not consumed... I like your term the energy is transferred.

 

Question:

Is the Law of Physics considered theory? If yes then why not Ohms Law considered theory? I don’t think the Late Ralph Morrison considered it theory.

His words:

Storing or moving energy.

There is a common misconception that signals are carried in conductors. Somehow this association crosses over to the idea that conductors carry both signals and energy. A few simple calculations can show that this is a false idea. Consider a 50-ohm transmission line carrying a 5-volt logic signal. The initial current at switch closure is 500 mA. A typical trace is a a gram-mole of copper that has 6 x 10²³ copper atoms (Avogadro’s number). Each atom can contribute one electron to current flow. Knowing the charge on an electron makes it easy to show that the average electron velocity for 500 mA is a few centimeters per second. What is even more interesting is that only a trillion electrons are involved in this current flow. This means that only one electron in a trillion carries the current. This also says that the magnetic field that moves energy is not located in the conductors. The only explanation that makes sense is that energy in the magnetic field must be located in the space between two conductors.Conductors end up directing energy flow - not carrying the energy.

The electric field in the conductor that causes current flow presents a similar picture. For a transmission line trace 5 mils above a ground plane, the electric field strength in the space under the trace is about 49,000 V/m. The electric field inside the conductor might be 0.1 V per meter. Energy in an electric field is proportional to field strength squared. The ratio of the square of field strengths in and near a conductor is about 2.4 x 10¹¹. It is safe to say that there is very little electric or magnetic field energy in a trace or conducting plane. Since the energy is present and it is not in the conductors it must be in the space between the conductors. This is true for sine waves or square waves at all frequencies including dc. This one idea is not often discussed in circuit theory. This one idea solves most interference problems. This one idea is at the heart of a good circuit board layout. If the energy that represents information is carried in spaces it makes sense that we must keep these spaces free from interfering fields. The path should also control the characteristic impedance so there are controlled reflections. What we really need to do is supply a smooth path for logic energy flow.

The math part is over my head... Do you disagree with what Morrison said? Where would you differ?

 

Can we say as a matter of fact the signal does not travel in the conductor but rather outside the conductor in the space between the conductors?

Would you agree the signal voltage creates the EM wave? If not how would define, explain, it.

Also am I wrong in saying there are multitudes of varying signal EM waves in a typical analog recording? Vocal(s), musical instruments.. I would say it is quite complex to say the least. Am I wrong?

Best regards,

Jim

@jea48,

 

Since the energy is present and it is not in the conductors it must be in the space between the conductors. This is true for sine waves or square waves at all frequencies including dc. This one idea is not often discussed in circuit theory. This one idea solves most interference problems. This one idea is at the heart of a good circuit board layout. If the energy that represents information is carried in spaces it makes sense that we must keep these spaces free from interfering fields.

I don’t really like this statement for a few reasons:

• The electrical field is predominantly between the two conductors. Not exclusively but predominantly,
• While true at DC, this creates a false impression of what will/is happening. If you have two stationary potentials, you can have an e-field, but there is no induced current and hence no magnetic field and hence no Poynting vector, no energy transfer. At least one of those wires must varying in potential which will cause a varying electrical field which will cause the electrons in the other wire to move, inducing a magnetic field, hence energy transfer. You may recognize this by a different name. Capacitor! Hence why in the real world, when people are working on PCBs, they use parasitics extraction software to model the unintentional capacitors and inductors. That is done at the chip level too.
• Just keeping the "spaces" between two conductors involved in the transfer of a signal, where most of the field is, "clear" of fields is only 1/2 the problem. The issue is other non-static fields between either wire and other things. There is both the issue of electrical fields and magnetic fields for interference of course and I don’t think this description does a good job of magnetic interference.

 

Can we say as a matter of fact the signal does not travel in the conductor but rather outside the conductor in the space between the conductors?

We can say that energy is transferred in the space outside the conductor predominantly. I personally don’t like to use the word signal, as the "signal" at least in an analog form is impacted by the nature of the conductor and if the conductor alters the signal, then you cannot negate that it is involved in information transfer, even if they energy is outside the conductor. I say that as a personal viewpoint. Others may take a less nuanced or alternate view.

Would you agree the signal voltage creates the EM wave? If not how would define, explain, it.

The signal voltage moves the electrons which creates the magnetic field which together are an EM field. However, a magnetic field can move electrons and moving electrons (charges) in a magnetic field induces an electrical field so ... chicken and egg.

 

Is the Law of Physics considered theory? If yes then why not Ohms Law considered theory? I don’t think the Late Ralph Morrison considered it theory.

Ohm’s law is neither a law nor theory in the traditional sense. It is a best an empirical law, and at worse an inaccurate definition, the original definition being that other conditions keep constant, the current in a conductor will be proportional to the applied voltage. Somewhere along the line it became I = V/R, which with a theoretical perfect R is true, but this is really a definition, not a law. This is much different from say laws of thermodynamics which are universal in their application and appear inviolable, but even that is up for debate.

 

Also am I wrong in saying there are multitudes of varying signal EM waves in a typical analog recording? Vocal(s), musical instruments.. I would say it is quite complex to say the least. Am I wrong?

 

I almost don’t want to answer this. Conceptually this is different from say photons (light) singular with specific wavelengths and energy potential. If you look at the electrical field, technically every single pair of excess charges creates a field, so there is not a multitude, there is a near infinite number, and every accelerating electron also has associated a magnetic field that other electrons interact with as well. So there is at once a near infinite number of fields, and one overall field.

You will note I said fields, and not waves? That was intentional. Electromagnetic waves are self propagating electric and magnetic fields travelling in free space. That is not what we are dealing with. We are dealing with propagating and varying electromagnetic fields. --- Anything beyond this gets too complicated and we get into propagating and non propagating solutions to Maxwell’s equations, wave functions, etc. By generally accepted definitions, what occurs in conductors is not EM waves, but propagating time variant EM fields. A key differentiation is EM waves are self oscillating, but the fields in our circuits are not.

 

 

 

 

 

 

 

after following this academic debate, and how/if it matters for audio signal transmission, I am left with some questions.  How does the insulation and multistrand design of most of our cables enter into this discussion?  Secondly, in light of the role of the fields around the wires, does the separation of the two wires ultimately have an effect?  AND FINALLY, though this all may matter for those that design  cables, to the end user, isnt the sound all that matters?

@rodman99999 

Thank you for posting the links.  

I have only one theory and that is:  As a species we simply don't know a tenth of a percent about anything.

We may know what works and what doesn't but that's about where it ends.  I'm not attempting to be cute or controversial...call it a belief system if you like.

I'm happy that this posting didn't go off the rails like the last one and enjoy reading this thread.

Regards,

barts  

@jw944ts ,

How does the insulation and multistrand design of most of our cables enter into this discussion? 

 

How? Well if I am trying to sell cables that realistically don't sound any different from anyone else, but I want to make it seem like maybe, perhaps it does, then I will bring up insulation, and all kinds of other things that technically have a measurable impact on the wires, but for the purposes of analog audio are completely meaningless so that I can appear differentiated.

 

multistrand design

Flexibility and does improve skin effect but I expect skin effect is not an issue unless you are running a single solid core 18awg, which I don't think anyone is are they?  That was a quick back of envelope estimate for where it may be an issue.

 

Secondly, in light of the role of the fields around the wires, does the separation of the two wires ultimately have an effect?

 

Yes it increases inductance. In any normal construction this is likely to have no audible impact. A poor cable and electrostatic speakers from my limited research may have an issue. I did a quick review of a bunch of speakers impedance plots after my discovery about the high Fidelium resistance.

 

I will raise the issue that for all the marketing claims of cables, the only specifications I could find where inductance, resistance and capacitance. One or two alluded to skin effect, but nothing concrete. No other parameters were provided.