Electricity misinformation

@sonhouse said
@Metal-Brain
It was needed at that time. We cans till do high voltage DC if we want to bad enough. It would make for less RF pollution but even if you have DC going to a comp say, the comp itself produces RF noise so that can be worse than line noise.

I am a ham and have very good radios and they pick up every dam rf noise my house makes, the worse from my Samsung clothes dryer, I have to actually unplug it from the power line to get rid of that noise, very loud.

@Metal-Brain
Not sure what I am agreeing with.

@metal-brain said
It is a good thing Tesla refuted Edison's scientific knowledge. Wouldn't you agree?

@Metal-Brain
Well he refuted it for his generation but now over a century later, technological developments make it possible to get both worlds, high efficiency with ultrahigh volt lines and less radiation of energy away from the wires.
In a 3000 mile run the mere length is a good portion of an antenna at 60 Hertz and a full wavelength at that frequency is about 3100 miles so it can radiate unless they can suppress that radiation, I can imagine circuits to do that but not sure what they do or if they deal with that at all, my HV supplies only went to 400,000 volts and the accelerator column, a series of large washers a foot in diameter with a hole in the center, with voltage drops across each one, that made a voltage gradient to accelerate ions, usual max at 200KEV but one was twice that. And those supplies were all DC, all the ion generation portion used HV supplies, 25KEV and up to 80KEV just to get ions out of the ion source then get re-accelerated by the big accel column. The only AC supply was for steering the ion beam, sweeping it back and forth like a spray nozzle over a surface to even out the coating or doping as we called it because the ions penetrate the surface and bury a more or less exact depth which is what you need to make semiconductors of any kind.

And of course science inches towards room temperature superconductors, then we are into a whole new ballgame, maybe buried high energy superconductors not needing cooling, whole new avenues for all kinds of electrical devices, cell phones needing a thousand times less energy, or electric car with a hundred thousand mile battery and the like, power tools never needs batteries because of so much stored energy.

@sonhouse
You are digressing away from my questions to evade those questions.
I have a simple question that should move things forward again.

Which current moves through a wire to the circuit faster, DC or AC?

@Metal-Brain
There are time related effects of AC flowing through wires but mainly it is the effect of tending to force the electrons in a wire to flow near the surface of the wire, consider the wire to be a cylinder of some diameter and looking down the edge of that conductor, at high RF frequencies, electrons gather towards the surface and in the extreme, say Gigahertz frequencies, the center of the conductor is more or less void of electron flow.

Having said that, if you dive deep into the electron's territory, on a micro level, the motion of the electrons are not in a straight line and they bounce around in a room temperature conductor sideways about as much as they progress into the wire.

So if you put a timer on the signal, say a very fast pulse of RF at a high frequency and you try to use a wire, the energy sits mainly on the outside surface of the wire.

That was a hint back in the days leading up to WW2, they used that effect and developed waveguides, which is a modified tube specifically to conduct very high RF frequencies, like in my old AF radar, 10 Ghz and the waveguide had a specific size to maximize transmission of said RF.

Not totally sure of exact difference of energy flow of AC V DC, but in either case at a nanolevel look, electron move to electron move, the distance is way shorter than any wavelength WE can pump through wires so the stochastic look means it hits some energy barrier and bounces at some odd angle or other, randomly, but the electric field driving the electron is still present and sweeps the electrons forwards, but in AC, forwards and backwards so actual flow is a wee more complicated.

@sonhouse said
@Metal-Brain
There are time related effects of AC flowing through wires but mainly it is the effect of tending to force the electrons in a wire to flow near the surface of the wire, consider the wire to be a cylinder of some diameter and looking down the edge of that conductor, at high RF frequencies, electrons gather towards the surface and in the extreme, say Gigahertz fr ...[text shortened]... the electrons forwards, but in AC, forwards and backwards so actual flow is a wee more complicated.

@Metal-Brain
You do know what AC is right? ALTERNATING current?

That means that energy can flow without a total flow of electrons through the system.
In AC the distance traveled depends on the frequency.
So a high voltage power line at 60 Hertz powered up has enough room for electrons to go from one side of the power grid, say Seattle, to the other side say in Philly.

But the speed of light is constant and the speed of DC flow through wires runs something like 10% of c because they bounce around so much two steps forward, one step back.

But in RF electrons only travel about as far as one wavelength, so a loop of wire some distance long, much longer than the wavelength, THOSE electrons only move so far then go backwards in response to the opposite polarity of the charge.

So a 300 mhz signal going through a wire only moves about one meter which is the wavelength of 300 Mhz.

So in that case the electrons just go back and forth up and down the wire.

So there is no net movement of electrons, like if you could tag one you would see it just going up and down the wire, confined to that space but energy still gets done.

You really don't like to search for yourself but here is one where they talk about the speed of electron flow in RF, which is not very far, they just go back and forth a distance depending on frequency, higher the frequency, the shorter their actual path.

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/miccur.html

@sonhouse said
@Metal-Brain
You do know what AC is right? ALTERNATING current?

That means that energy can flow without a total flow of electrons through the system.
In AC the distance traveled depends on the frequency.
So a high voltage power line at 60 Hertz powered up has enough room for electrons to go from one side of the power grid, say Seattle, to the other side say in Philly. ...[text shortened]... , the shorter their actual path.

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/miccur.html

@Metal-Brain
The answer is DC is the version where electrons move from one end of the wire to the other.

Why don't you try reading the link, AC doesn't actually move much, just goes back and forth with the distance traveled is the size of the wavelength, so one meter, 300 Megahertz the electrons can only travel one meter out and one meter back but if you look at each electron in an AC wire, so the electron moves 2 meters per cycle.
If the wavelength was one cm, the electrons go one cm in and then one cm back.
But that is a group thing in the wire, they are all going at the same time more or less, depending on wire impedances, capacitive reactance, inductive reactance but in DC circuits, the same electron could theoretically be tracked from the time it leaves the battery to the time it gets back to the same battery, the same electron makes the trip all the way round.

Not sure what your question is.

@sonhouse said
@Metal-Brain
The answer is DC is the version where electrons move from one end of the wire to the other.

Why don't you try reading the link, AC doesn't actually move much, just goes back and forth with the distance traveled is the size of the wavelength, so one meter, 300 Megahertz the electrons can only travel one meter out and one meter back but if you look at each ele ...[text shortened]... same battery, the same electron makes the trip all the way round.

Not sure what your question is.

@Metal-Brain
You area looking at a situation where if electrons were in a hollow tube with vacuum they would be going very fast but in a wire, not so fast, nothing like c.
But you might think of RF as bundles of energy going down the wire and in this case you could have a tube filled with dozens of say balls, representing each wave on the wire.
But in this case, they are all lined up in the tube and now you whack the ball at the end and that ball whacks the next and so forth till the balls have all received a kick so at the other end, the kick does its job, whatever that was supposed to be but the electrons didn't move much, just oscillating back and forth inside the wire.

DC on the other hand just has to deal with the electrons banging into stuff, bouncing around and ending up going pretty slow.

There is an instrument called a time domain reflectometer, which is exactly like a radar except the main bang pulse just goes into a wire and the job of it is to find an impedance discontinuity like a poorly spliced wire. So the frequency of the pulse would be very high if it was a continuous wave but it it pulsed so if you want a range of a mile, that is, check out a full mile of wire, you have to have pulse width in nanoseconds, it meanders down the wire and encountering a fault, just like radar in air, some of the energy in the pulse goes backwards to the source.

So you count how many nanoseconds it took from the time the pulse enters the wire to the time a return is noted, and a very exact timer can work out exactly how far down the wire the fault lies.

So the speed of the pulse is known very well going down wires, and subtleties like copper V aluminum conductors, and the like, all that is known also and in the equations used to get the distance to faults.

That is not rocket science, been around for decades.

@sonhouse said
@Metal-Brain
You area looking at a situation where if electrons were in a hollow tube with vacuum they would be going very fast but in a wire, not so fast, nothing like c.
But you might think of RF as bundles of energy going down the wire and in this case you could have a tube filled with dozens of say balls, representing each wave on the wire.
But in this case, they are ...[text shortened]... quations used to get the distance to faults.

That is not rocket science, been around for decades.

@Metal-Brain
The real question is why you think that is some kind of new news.
Trust me, it is not. I suppose you think physicists are SO stupid they cannot consider electromagnetic fields.
Oh, I forgot, WE are the stupid ones and YOU and your buddies know more than anyone else on the planet.
God, why did I forget that?