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# How Electricity Works

11/21/2021 8:04 PM

Here is an interesting explanation of how power moves from source to load in an electrical circuit. Do you agree with his answer to his puzzle?

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#1

### Re: How electricity works

11/21/2021 10:43 PM

Then why do loose connections heat up? Anyway to me anytime you approach the speed of light you are entering an unknown realm of black box magic, who knows what's happening if for the electrical flow time is nearly standing still? ...or is that just a human perception?... as somebody who has sparked many wires in my day, the electrical flow is in the wires it seems to me...now you could explain it any number of ways, does the electrical flow propagate the magnetic field or does the magnetic field propagate the electron flow, or is there no electron flow at all? All I know is that if you are going to troubleshoot electric circuits, you better assume the electricity flows in the wire...

A strong magnetic field can definitely influence the rhythm of the electric flow, but I don't think it could stop it, it would have to be stronger than what would be considered common...it would be interesting to try...

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#2

### Re: How electricity works

11/21/2021 11:58 PM

I love most of his videos but I have many problems with this one.

First, Maxwell combined the work of many others (Coulomb, Faraday) to make a more cohesive understanding of their separate work on electric or magnetic fields. Maxwell linked the two fields together and Heaviside combined Maxwell's original equations into the four equations we now call Maxwell's equations.

Second, the chain in a tube analogy or model is a teaching model. All models are wrong. Some models are useful. This model is useful in teaching about the need for a closed-loop.

Third, the electric field and the magnetic field around a conductive wire decrease proportionally with the distance from the center of the wire, not the surface of the wire. The electrical energy (Poynting vector), therefore, decreases proportionally with the square of the distance from the center of the wire. Most of the energy is close to the wire but it resides outside of the conductor.

I like his observation that energy still transfers from source to load, regardless of voltage polarity.

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#3

### Re: How electricity works

11/22/2021 8:54 AM

He's saying power flow is through the electric and magnetic fields. Current flow is obviously in the wire. Voltage drop creates an electric field and current flow creates a magnetic field, so the product of voltage and current amounts to the same thing as the cross product of the electric and magnetic field vectors, except that the latter also provides direction. It also describes power flow when there are wires involved (or waveguides, etc.) using the same Maxwell equations that describe power flow through electromagnetic radiation.

https://www.cuemath.com/geometry/cross-product/

I'm still trying to get my head around his puzzle with the extremely long circuit. He is saying that after the switch is closed, some power would reach the light bulb in the time it would take for the magnetic field to reach it.

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#4

### Re: How electricity works

11/22/2021 10:07 AM

Here's an annoying semantics/mathematics argument.

The electric and magnetic fields are formed outside of the conductor surface as described. The calculated Poynting energy vector produced by the cross product (curl) of these fields requires resides inside the wire conductor, too. The fields lie outside of the conductor but the energy (power) lies within the conductor, too.

My point here is the Poynting vector, electromagnetic fields and electric power are actually human constructions that happen in our minds. They are models of how the universe works. They are not in the physical universe itself. All models are wrong... I believe this apparently paradoxical statement that electric power does not travel inside a conductor is a misleading application of Physics and Mathematics.

{I warned you this would be an annoying argument.}

I too am unhappy with the puzzle of an extremely long circuit. When the switch closes the electric field between the switch and load will quickly change as current begins to flow. How quickly this occurs is the crux of the problem? Only the lengths of the circuit in one dimension are presented to solve this three-dimensional question.

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#5

### Re: How electricity works

11/22/2021 1:16 PM

Whether fields actually exist, I guess, is a philosophical question. When I hold two magnets in my hands, it sure feels like there is something real in the space between them.

As for the skinny circuit puzzle, here is my analysis. (I reserve the right to be wrong. )

1. Initially, the switch is open. The wire between battery and switch is at a negative potential. The wire from battery out and back to the lamp, the lamp itself, and wire out and back to other side of switch is at a positive potential. No current is flowing.

2. The switch is closed making both sides the same potential. A positive voltage step will propagate to the right, and a negative voltage step to the left. Across each step transition, current will flow from the high to low side (current pulses). Associated with each voltage step and current pulse would be a Poynting vector from the battery to the lamp.

3. Perhaps the transients can couple some energy across the 1 meter separation to the wires connected to the lamp in 1/c seconds, but I believe most of the power doesn't arrive at the lamp until the transients have gone around the long way.

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#6

### Re: How Electricity Works

11/22/2021 1:29 PM

Hey, I still don't understand why the stuff doesn't drip out of the outlets

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#7

### Re: How electricity works

11/22/2021 4:27 PM

A bit of history: Oliver Heaviside predicted/discovered what is now mostly called the ionosphere. He may also have originated the term for what had been known as the Heaviside Layer. The earlier term was used in the musical "Cats", based on a T.S. Eliot work.

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#8

### Re: How Electricity Works

11/22/2021 11:17 PM

Using a one pole switch allows the circuit to distribute the voltage potential all around the circuit.

As soon as the switch contact sparks, current begins. The voltage circuit only has to cross the contacts. A short distance. A quick distance.

Try a two pole switch and time it again.

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#9

### Re: How electricity works

11/23/2021 12:42 AM

I agree with all three points.

When I taught physics, I commonly used a tube full of bearing balls or marbles to represent a wire full of electrons. when you push an additional ball into one end of the tube, a different ball is forced out the other end almost immediately. The almost is important: In the case of balls, there is a tiny time required for each ball to react to the additional pressure exerted by its neighbor, become compressed, and pass that pressure on to the next one.

A wire is "full" of electrons. Pushing an additional electron in one end of the wire causes it to repel the electrons already present in that end of the wire, and those electrons repel their neighbors, etc. to the other end of the wire. Since electrons do have mass, I believe the pulse of repulsion that travels down the wire must travel with a velocity somewhat slower than c.

It's a little harder to illustrate, but the same thing must happen when pulling an electron out of the other wire. Since the illustration shows a distance of one light-second out each side, each pulse must take somewhat longer than a second to reach the outermost point, and another second plus to return to the light bulb. Thus the closest answer of his choices would be 2 seconds.

Perhaps trivial, perhaps not: His diagram uses the standard symbol for an incandescent lamp, while his physical circuit used an LED lamp. (The heat-sink between the bulb and the base is the indicator) Incandescent lamps require significantly more current, and take significantly longer to reach normal brilliance than LED lamps.

Quite a few years back, here on CR4, there was a discussion of why certain AC LED lamps continued to glow dimly when the switch was in the Off position. The ceiling LED lamps in my hallway are that way. I was able to show that it was due to capacitive coupling between the wire connected to the lamp, but disconnected at the switch, and the "hot" wire in that same 3-wire cable. Thus your point about coupling energy from the outgoing to the incoming sections of the wire definitely has merit.

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#10

### Re: How Electricity Works

11/23/2021 4:59 AM

I beg to differ, being an electrical technician I can tell you it has nothing to do with holes and electrons but with smoke travelling in the wires.

Let the smoke out and the party is over. Power stations only spew smoke out because they make too much smoke to cram into small wires and it has to be vented else the buildings would choke up and cause OHS to have a catatonic fit.

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#11

### Re: How Electricity Works

11/23/2021 6:32 AM

Because electrons repel each other they try to conform to the lowest energy state which is as far from each other as they can get. The result is that current flows on the surface of a wire rather than in the center. Power station generators produce electricity at a relatively low voltage to reduce the amount of insulation needed in the coil windings. This low voltage is transferred to as soon as possible a step up transformer (GT) so that large amounts of energy can be conducted with much smaller cables. The short bus bar link between the generator and the GT is usually made of copper tube or toe to toe <> or [] sections, (the vertical gap in the < & [ sections helps heat dissipation so increases capacity). This configuration is used because if current is not flowing through the middle of a conductor, why have a middle? In the 1970's copper coated aluminum cored cable was developed for standard house wiring to capitalize on this effect but corrosion issues made it impractical and it's production was discontinued.

A different technique is used to reduce the amount and weight of copper needed in high voltage overhead transmission lines. The high voltage ionizes an air layer around the cable so that it forms a tube of ionized gas co-axial to the cable. This gas acts as a conductor and like in a copper wire most of the current flows on the outer surface of the ionized layer rather than the copper. Often each phase of HV transmission lines has four conductors with X shaped separators spaced along the conductors roughly every hundred feet to hold the wires apart (closer in very windy locations). The four separated conductors create a bigger ionized layer so increase the transmission capacity without increasing the cost and weight of the copper.

I have deliberately not responded to the puzzle question. Idealized wires with zero resistance do not exist so any answer I could give would be meaningless. Such questions can be put to theorists but not to engineers. Resistance, capacitance, inductance, cross sectional area, type of insulation, location of the wires (above/on/under the ground), the two phenomena listed above would all have effects that could alter the timing.

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#12

### Re: How Electricity Works

11/23/2021 7:52 AM

As I have explained in a previous post ,the smoke coming from the power stations is a result of all of the dark being sucked out of the environment by light bulbs.

It can easily be seen in the black spot on blown bulbs when they have reached their dark capacity.

Particles of soot are simply concentrated dark.

Even stars can reach maximum dark capacity and turn into black holes.

Over 90% of the universe is dark,and stars can only absorb a small amount.

Dark matter is debris from a black hole formation,scattered by the implosion,stripped of all of the normal characteristics of Barionic matter,sort of like cream rising to the top of milk.

All of this I learned from my 5 year old grandson.

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#13

### Re: How Electricity Works

11/23/2021 8:01 AM

Electron flow is less than C in the conductors,but the magnetic field is not constrained so it will move at C,arriving ahead of the electrons.Like charges repel,so most of the electrons will be in the outer edges of the conductors.Some high frequency conductors are hollow tubes rather than solid.

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#14

### Re: How Electricity Works

11/23/2021 8:19 AM

In addition to the corrosion issues,the aluminum expanded and contracted when heated by the load,and it was so soft,it created a gap when it cooled,loosening the contact with the screws and this gap increased at every heat cycle,eventually creating an arc,which of course,caused many fires.The modern alloys for branch circuits,after 1972,are available but require fixtures rated for such use.

Most contractors will not use them for branch circuits regardless,because of potential liability issues even though they are UL approved ,but require special rated receptacles and connectors.

Most mains feeders now are aluminum,and these larger sizes and newer alloys are not a problem.

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#15

### Re: How Electricity Works

11/23/2021 9:43 AM

This assumes that the speed of light/electromagnetic waves is independent of the media through which it is passing. That is not the case. As an example light passing through a diamond crystal with a refractive index of 2.42 travels at 124,000km/s not the 300,000km/s commonly quoted which is the speed through air.

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#16

### Re: How Electricity Works

11/23/2021 10:57 AM

Motors are routinely connected to conductors that have been drawn into long runs of rigid steel conduit (that is: encased in heavy ferrous shielding), and those motors run just fine. Is this reality in conflict with the assertion in the video that energy is transmitted by the electric and magnetic fields? The reason given for the failure of the first trans-Atlantic submarine cable was that it was encased in an iron sheath that "interfered with the propagation of the electro-magnetic field". Why are motors fed by conductors in steel conduit unaffected by the attenuation of the fields which are purportedly providing the energy for their operation?

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#17

### Re: How Electricity Works

11/23/2021 12:24 PM

posted in error

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#18

### Re: How electricity works

11/23/2021 6:25 PM

There really are a lot of electrons in a wire.

A collection of 6.2415 × 1018 electrons has a charge of one Coulomb

A cubic centimeter of copper contains approximately 8.4 × 1022 free electrons at room temperature.

So 1 amp flowing through a 1 cc cube (cross section = 1 cm2) flows at a rate of Vc = 6.2415x1018 / 8.4x1022 = 7.43x10-5 cm/sec

To figure the flow rate for various wire gauges, calculate the cross sectional area, A=Π*(D/2)2. The velocity for current I will be V = I*Vc/A cm/sec

 Gauge Dia mm Area cm2 Velocity cm/sec 10 2.6 0.0530929 0.00139943 12 2.1 0.0346361 0.00214516 14 1.6 0.0201062 0.00369538 16 1.3 0.0132732 0.00559773 18 1 0.00785398 0.00946017 20 0.81 0.005153 0.0144188 22 0.64 0.00321699 0.0230961 24 0.51 0.00204282 0.0363713 26 0.41 0.00132025 0.056277 28 0.32 0.000804248 0.0923845 30 0.26 0.000530929 0.139943 32 0.2 0.000314159 0.236504 34 0.16 0.000201062 0.369538
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#19

### Re: How Electricity Works

11/23/2021 8:07 PM

3000 miles of iron sheath made the cable a large inductor. An inductor opposes the change in current and sending a signal through the cable requires changing the current for "dots and dashes". The larger the inductance, the more voltage is required to change the current by a given amount. A mechanical analogy is the large force needed to shake a very heavy weight.

The steel conduit does result in some series inductance in the motor circuit, but far less than the coils in the motor and not a problem.

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#20

### Re: How Electricity Works

11/24/2021 3:36 AM

Your grandson is progressing well and will likely graduate as an Iron Stein, which due to the corrosive nature of the imbibing liquid will turn to rust.

Having worked in a power station before I know the troubles of collecting the dark and returning it to the generators. One thing that happens which is given little notice these days of so liar and whinge farming is the fact that insects become trapped by the collection of dark. This can be proved by the amount of fly ash that is collected and sold to cement companies.

Just think of the number of flies that are senselessly cremated daily to produce so much fly ash. Fly lives matter too!

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#21

### Re: How Electricity Works

11/24/2021 5:04 AM

Three men are debating in a pub one night about the fastest thing in the universe: the first says

"It must be electricity, if you walk into a huge hall and flick the light switch the lights come on even at the far end of the hall immediately."

The second says "No, I think its thought: I can be sitting still when there is a bang behind me, my head can be full with a hundred thoughts instantly."

The third man says "No, its got to be diarrhoea : I had the sh*ts last night and I didn't have time to think or put the lights on."

Sorry.

I didn't follow the whole argument. Is it necessary for the circuit to extend to both sides, or, would this exhibit the same behaviour.

When the switch X1 is closed the RHS of R1 should rise in x/c seconds where x is the distance between X1 and R1.

If so this is easy to check with a modest length of wire and a high speed scope.

(It's easy to see the 1ns difference between a 3' and a 4' scope probe when they're both probing the same point.)

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#22

### Re: How Electricity Works

11/24/2021 5:40 AM

He also said that fireflies have a small mouth,so they can only chew a certain amount of dark at one time.This is the reason they blink between bites.

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#23

### Re: How Electricity Works

11/24/2021 5:49 AM

IMHO:

The electromagnetic wave extends outside of the conductor,through the air,and moves faster than the field within the conductor itself.

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#24

### Re: How Electricity Works

11/24/2021 9:19 AM

Muhammad Ali had this to say on the subject: "I'm so fast that last night I turned off the light switch in my hotel room and was in bed before the room was dark."

I can't find the quote but remember him saying that it was not a phantom punch that KO'ed Sonny Liston in their 1965 bout. Ali said that his punch was so fast it happened between the frames of the movie camera and that's why it can't be seen in any footage.

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#25

### Re: How Electricity Works

11/24/2021 3:04 PM

Changing current has a longer path to follow than the voltage path. The voltage path is straight down the conductor. But changing current has a radial component to it's axial component. So it spins around the conductor. You can see this for yourself with ferrofluids. With the fluids, the change needs to be slow, because of the fluid inertia. But you can confirm this yourself.

Current does not stop when charging a coil.....it spins like a spring.......when the voltage falls....the spring unwinds.......giving a delay.

It spins left on charge and right on discharge.

Current is the result of zillions of intermittences.

An isolated wire, or a neutral wire, has a disassociated current all the time. It's multi-directional due to temp and external static. A film of room temp plasma on the surface of metals.

If we put a voltage across the wire, a PORTION of the disassociated current will align and move in one direction. The portion of the disassociated current that is already in that direction, are the first to flow.

The individual charge movement is short lived. It collides and bounces...... the bounce can go in any direction, so it can not be detected as current, only the forward aligned charges can be measured.

With so many intermittences, a steady current is perceived.

Along with the alignment of the charges, the M dipoles of the charge also line up. This puts a radial force on the velocity of charge, when adding charge or subtracting charge from the current.

Making current spin and spring. At the last 1/4 WL of an open conductor, you will find a current or charge spring.

If one disassociates that charge spring in quick manner, the field of that spring, will be emitted in an instant.

EM radio emission(light) is intermittent also. And explains physicality without space time.

Radio is not a wave. It's intermittent strobes. Only the detector(because of inertia) oscillates.

As for conductor current, the flow(current) is only a means to align charge.....the alignment does the work.

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#26

### Re: How Electricity Works

11/24/2021 4:08 PM
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#27

### Re: How Electricity Works

11/24/2021 11:10 PM

How Illuminating your observations are, I thank you for the share but not the sunny.

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#28

### Re: How Electricity Works

11/25/2021 8:55 AM

Even in the deepest depths of the ocean,dark suckers exist.

The mass of the dark is greater in water than in air,so the dark suckers are simply overwhelmed by the dark.

There are some dark suckers that sometimes surface when stirred from the depths or disturbed from their sleep by agitation.

It is Turkey Day over here,(AKA Thanksgiving),so I will probably overeat as usual,then take nap,turning off the dark suckers in my room.

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#29

### Re: How Electricity Works

11/26/2021 4:03 AM

Not everyone gives thanks for the turkeys surrounding us, sometimes it is just gobbledy gook! Enjoy your venture in to the dark space, sucker free!

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#30

### Re: How electricity works

11/27/2021 9:38 AM

The Poynting theorem that explains power transmission is only a mathematical model. I'll ask. Are electric and magnetic field physical reality? I seem to think they are just analytical concepts using mathematics, not physical reality. The Poynting theorem talks about energy flow, but tells nothing about the actual physical mechanism that "carries" energy around. If they tell me photons, then if I accept photon to be light particles carrying energy, then we have the corresponding physical mechanism. But the Poynthing theorem itself is not directly related to the photon concept. On the other hand, we are very clear on what the physical mechanism for current flow is, the flow of electrons.

Veritasium's answer 1/c sec for the bulb to light up is clearly wrong. What we expect is about the flow of power from the battery on average; if the bulb is 5 watt, we should be talking about 5 watt flow of energy from battery to bulb, not any infinitesimal transient energy from battery jumping the 1 meter space to the bulb. If a current flow is established and the circuit is broken, then there will be a delay of about L/c sec before the bulb dims, L = 300,000,000m.

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#31

### Re: How electricity works

11/27/2021 1:28 PM

Oops. Not L, but c=300,000,000m

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#32

### Re: How electricity works

11/27/2021 8:42 PM

There is a delay of 1 sec if L= 300,000,000m. Veritasium's assumption would have been near instantaneous, 1/c sec.

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#33

### Re: How electricity works

11/27/2021 10:50 PM

I can't find the original drawings now, but if I recall correctly, it showed the distance of 300,000,000 m from center to each end of the loops. I interpret that to mean that L=600,000,000 m. (600,000,001 m, if measured to the nearest meter).

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#34

### Re: How Electricity Works

11/28/2021 1:48 AM

I think it is easy to confuse the E, M of electromagnetic fields with this case of the electric field and magnetic fields generated by the current along the wire. If we assume a steady state reached, then the E and M fields around the conductors do not "travel" and have no "speed". Only power flow has a speed. I am not sure if Poynting theorem itself says anything about speed of power transfer. But if it is the same as the speed in the telegrapher's equation, then it is near c. So time = L/c , L= length of conductor. Verasatium is wrong.

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#35

### Re: How Electricity Works

11/28/2021 7:54 AM

I'm surprised it has taken this long for anyone to mention the inductance of wires. The link shows that of the four variables needed to calculate inductance one variable is given and one can be assumed but insufficient data is provided to attempt a calculation.

Inductance, Capacitance, and Resistance (per unit length) are the attributes that determine a transmission line. None of those attributes can be determined from what is given.

Veritasium is ignoring the Physics of this poser for a preconceived result.

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#36

### Re: How Electricity Works

11/28/2021 3:59 PM

I'm so poor at electric stuff that it's hard to tell when you guys are spoofing! I like the Lucas explanation mentioned earlier: Don't let the smoke out of the wires. Problems with Lucas' electrical systems on cars was given as the reason they invented intermittent windshield wipers. Also why Brits like warm beer--because unheaters (refrigerators) don't work well.

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