Does the Skin Effect cause charge to accumulate on the surface of a conductor?

[Sibilo]

good morning gentlemen, I would like to ask you a fairly simple question but which I am unable to resolve. Then considering the "skin effect", which involves an increase in resistance to the passage of current with consequent generation of eddy currents, this leads to an accumulation of charges on the surface of the conductor. Here's how I can make as many charges as possible accumulate on the surface of the conductor, and not inside? I want the conductor to be completely wrapped on the surface by electric charges, what can I do?

 

[Baluncore]

Welcome to PF.

I want the conductor to be completely wrapped on the surface by electric charges, what can I do?

You need to charge the conductor relative to its environment or earth.

The capacitance of the conductor is fixed by its geometry and position.
C = Q / V; to maximise Q, with fixed C, maximise V.
Connecting it to a high voltage will maximise the surface charge.

The skin effect is unrelated to surface charge. Skin effect increases the conductor resistance, by reducing the available depth of conductor, for rapidly changing surface currents.

 

[berkeman]

Here's how I can make as many charges as possible accumulate on the surface of the conductor, and not inside? I want the conductor to be completely wrapped on the surface by electric charges, what can I do?

As @Baluncore says, you want to DC charge your conductor, not try to use the AC skin effect. To get a nice circular envelope of charge around your conductor, you can use a geometry like this charged coaxial cable (where the inner conductor has a uniform surface charge:

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

 

[Sibilo]

As @Baluncore says, you want to DC charge your conductor, not try to use the AC skin effect. To get a nice circular envelope of charge around your conductor, you can use a geometry like this charged coaxial cable (where the inner conductor has a uniform surface charge:

View attachment 333789
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capcyl.html

thanks for the answer, no, the surface is made up of many curves and is not cylindrical, so I think the current can accumulate at the tips. Yes, for the skin effect, a variable current is needed, which produces eddy currents (the real culprits). I'm not a physics expert, so I'm asking you. I would like the body to be wrapped only on the surface (about 1mm, therefore currents with a frequency of KHz) just as happens when you want to transmit with EM waves with an antenna, but I don't have to transmit

 

[berkeman]

Do you understand that current is the flow of free electrons in the conduction band of the conductor, not an accumulation of charge anywhere in the conductor?

Can you say what you are trying to do with this? Why do you want an accumulation of charge when you are trying to transmit EM waves? That's not how antennas work...

 

[Sibilo]

Welcome to PF.

You need to charge the conductor relative to its environment or earth.

The capacitance of the conductor is fixed by its geometry and position.
C = Q / V; to maximise Q, with fixed C, maximise V.
Connecting it to a high voltage will maximise the surface charge.

The skin effect is unrelated to surface charge. Skin effect increases the conductor resistance, by reducing the available depth of conductor, for rapidly changing surface currents.

I hadn't thought about the similarity with the faces of the capacitor. however by surface currents I mean currents that circulate ONLY on the surface and not at the internal and this is related to the frequency, and increasing the voltage increases the affected volume. Now bodies are not all the same and above all they have many curves, in this case how does the current conduct?

 

[Sibilo]

Do you understand that current is the flow of free electrons in the conduction band of the conductor, not an accumulation of charge anywhere in the conductor?

Can you say what you are trying to do with this? Why do you want an accumulation of charge when you are trying to transmit EM waves? That's not how antennas work...

yes maybe it's the translator who doesn't translate well, yes I know that electric current and electrostatic charges are opposites. in fact I'm talking about the passage of current. I don't have to transmit anything, no radio waves, I just want the conducting body to be surrounded by surface currents (skin effect), which is why they must be at high frequency >1KHz. I just want this, the fact is that om I know the specific parameters especially because the conductor has many curves and is not flat

 

[SongDog]

good morning gentlemen

Please don’t presume everyone here is male, gentile, or anything else.

 

[Sibilo]

Please don’t presume everyone here is male, gentile, or anything else.

Ok sorry

 

[SongDog]

yes maybe it's the translator who doesn't translate well, yes I know that electric current and electrostatic charges are opposites. in fact I'm talking about the passage of current. I don't have to transmit anything, no radio waves, I just want the conducting body to be surrounded by surface currents (skin effect), which is why they must be at high frequency >1KHz. I just want this, the fact is that om I know the specific parameters especially because the conductor has many curves and is not flat

Trying or not, if you have an alternating surface current you will transmit EM waves. It is inescapable when any charge undergoes acceleration (at least in classical EM theory).
To calculate a capacitance you must specify the two conductive objects involved and the dielectric between them.

 

[Baluncore]

I don't have to transmit anything, no radio waves, I just want the conducting body to be surrounded by surface currents (skin effect), which is why they must be at high frequency >1KHz.

If you manufacture the body, by 3D printing it, or by cutting it from an insulator, then make it conductive by depositing a surface film of copper, silver, or gold. The surface currents can then be from a DC supply, an AC supply is not needed.

An alternative would be to make it from thin metal sheet material, hollow, pressed into shape.

If you do not manufacture the conductor, then maybe you could identify what the object is, and why you require that only surface currents flow.

 

[Sibilo]

Trying or not, if you have an alternating surface current you will transmit EM waves. It is inescapable when any charge undergoes acceleration (at least in classical EM theory).
To calculate a capacitance you must specify the two conductive objects involved and the dielectric between them.

yes, to transmit you need to be in the far field but I stay in the near radiative field precisely so as not to transmit. there is no dielectric because the connection takes place with 2 cables, the first conductor is the copper wire that carries the charge while the second is any scrap

 

[Sibilo]

If you manufacture the body, by 3D printing it, or by cutting it from an insulator, then make it conductive by depositing a surface film of copper, silver, or gold. The surface currents can then be from a DC supply, an AC supply is not needed.

An alternative would be to make it from thin metal sheet material, hollow, pressed into shape.

If you do not manufacture the conductor, then maybe you could identify what the object is, and why you require that only surface currents flow.

no no, the body is a total conductor, that is, damp masses or a metal, scrap from a landfill, that's it. therefore the currents can also pass through it inside which is why I want to make them flow on the surface and now that I have found the method I want to implement it, but I want to know the exact specifications of current, voltage, frequency, etc...

 

[Baluncore]

no no, the body is a total conductor, that is, damp masses or a metal, scrap from a landfill, that's it. therefore the currents can also pass through it inside which is why I want to make them flow on the surface and now that I have found the method I want to implement it, but I want to know the exact specifications of current, voltage, frequency, etc...

Surface currents will flow in the metal, below the oxide, sulphide, or organic layer that will form on the bare metal surface.

The current will flow to points where it can escape the solid metal at a site of electrolysis on the surface, (corrosion or deposition).

A surface current has higher resistance than a full depth body current. That heats the surface, which is a disadvantage, except when induction hardening some metals.

Current flowing parallel to the surface is non-productive. What effect do you expect it to produce, that is not generated by a body current.

High frequency AC will have lower electrolytic activity than DC, since with AC, every cycle has a reversal of the electrolytic reaction.

Can you explain why for your application, you require the current to reach the exit point, only as an AC surface current ?

 

[Sibilo]

Surface currents will flow in the metal, below the oxide, sulphide, or organic layer that will form on the bare metal surface.

The current will flow to points where it can escape the solid metal at a site of electrolysis on the surface, (corrosion or deposition).

A surface current has higher resistance than a full depth body current. That heats the surface, which is a disadvantage, except when induction hardening some metals.

Current flowing parallel to the surface is non-productive. What effect do you expect it to produce, that is not generated by a body current.

High frequency AC will have lower electrolytic activity than DC, since with AC, every cycle has a reversal of the electrolytic reaction.

Can you explain why for your application, you require the current to reach the exit point, only as an AC surface current ?

thanks for the answer, I didn't understand the issue of the leakage points, the current follows the path with less resistance but in this case there is greater resistance. Yes, I would like the current to flow on the surface so that it produces an effect similar to what we feel when we feel a shiver, without going into the depths of the body

 

[Sibilo]

Surface currents will flow in the metal, below the oxide, sulphide, or organic layer that will form on the bare metal surface.

The current will flow to points where it can escape the solid metal at a site of electrolysis on the surface, (corrosion or deposition).

A surface current has higher resistance than a full depth body current. That heats the surface, which is a disadvantage, except when induction hardening some metals.

Current flowing parallel to the surface is non-productive. What effect do you expect it to produce, that is not generated by a body current.

High frequency AC will have lower electrolytic activity than DC, since with AC, every cycle has a reversal of the electrolytic reaction.

Can you explain why for your application, you require the current to reach the exit point, only as an AC surface current ?

you talked about AC and DC but it is the AC current that generates the eddy currents and therefore the skin effect, perhaps the direct current can generate the proximity effect if parallel to another flow of the same direction. however what I want is for the current to flow on the surface of the body and this happens at high frequencies then I don't think it will heat up much because I will make sure to make the conduction last a few seconds to minimize the joule effect

 

[Baluncore]

... the body is a total conductor, that is, damp masses or a metal, scrap from a landfill, that's it.

Is the metal exposed, to the air, or maybe in water ?

An electrical circuit must exist for a current to flow. How are the two connections made to the damp mass, or scrap metal conductor ?

 

[Sibilo]

Is the metal exposed, to the air, or maybe in water ?

An electrical circuit must exist for a current to flow. How are the two connections made to the damp mass, or scrap metal conductor ?

then the conductors can be either metals or wet (biological) masses, the connection occurs via two cables therefore by conductive coupling, simply by attaching 2 cables, so the circuit is already created, I only need the voltage, current and frequency values. the bodies are only quite extensive, about 2 m^2 in total surface area with many curves such as washing machines

 

[davenn]

then the conductors can be either metals or wet (biological) masses, the connection occurs via two cables therefore by conductive coupling, simply by attaching 2 cables, so the circuit is already created, I only need the voltage, current and frequency values. the bodies are only quite extensive, about 2 m^2 in total surface area with many curves such as washing machines

18 posts so far and everyone in just guessing at what you want
This is because you are not clear enough with your description of your setup

Show us a photo of your setup/experiment, how it's connected to the power supply ?

tell us the voltage ?
tell us what current you are expecting to flow ?
what is the source of this 1kHz signal ?

DONT ask any more questions till you answer the above questions

Ohhh and skin effect is going to be minimal at a couple of kHz
it doesnt really come into significant play till the multi-mega-Hertz frequencies

 

[Sibilo]

18 posts so far and everyone in just guessing at what you want
This is because you are not clear enough with your description of your setup

Show us a photo of your setup/experiment, how it's connected to the power supply ?

tell us the voltage ?
tell us what current you are expecting to flow ?
what is the source of this 1kHz signal ?

DONT ask any more questions till you answer the above questions

Ohhh and skin effect is going to be minimal at a couple of kHz
it doesnt really come into significant play till the multi-mega-Hertz frequencies

no but I haven't built the system yet so I can't post photos. I already said what I want at the beginning, I want to create the skin effect on the surface of a conductor with a length of 60 cm, I only need the values to carry out a surface current without transmitting EM waves and therefore remaining in the radiative near field, I just want to know the values

 

[davenn]

I already said what I want at the beginning, I want to create the skin effect on the surface of a conductor with a length of 60 cm,

but still your setup description is very unclear

if no photos, draw some pictures as neat and tidy as you can

 

[Sibilo]

but still your setup description is very unclear

if no photos, draw some pictures as neat and tidy as you can

but you don't really need a drawing, there's just a straight conductor (like an antenna) 60 cm long, that's all. I want to know the voltage, current and frequency values and the calculations for which the skin effect occurs. it can also be an electrolyte but it is not necessary

 

[davenn]

I want to know the voltage, current and frequency values

well you already know those 3 things -- they are whatever you feed the conductor with

Wiki has a whole article on skin effect and the calculations thereof
no point me repeating it

https://en.wikipedia.org/wiki/Skin_effect

 

[Vanadium 50]

"We're confused."
"No you're not."
"Yes, we are. We don't understand."
"Yes you do."

We can go on and on like this, or you could post a picture.

 

[Sibilo]

"We're confused."
"No you're not."
"Yes, we are. We don't understand."
"Yes you do."

We can go on and on like this, or you could post a picture.

Gentlemen, I haven't built the system because I'm still not sure of the values to use (voltage, current and frequency), otherwise the conductors I will use are iron rods like those used for antennas or metal objects or also electrolytes such as buckets of water with a mixture of sodium chloride to make it conductive. That is, mine are small experiments so there isn't a single conductor that I will use but many. I really don't need an image or photo in my opinion, I just need to know the formulas and ways to obtain the skin effect (far radiative field) for all cases of first and second species conductors (electrolytes) that's all

 

[berkeman]

I just need to know the formulas and ways to obtain the skin effect (far radiative field) for all cases of first and second species conductors (electrolytes) that's all

Then Dave's link should give you all you need, right? Have you read through it yet?

https://en.wikipedia.org/wiki/Skin_effect

 

[Sibilo]

Then Dave's link should give you all you need, right? Have you read through it yet?

yes yes I have already read it and I am trying to apply the theory to all types of conductors I hope to succeed, only I am unsure about electrolytes, in this case I don't know if the physical laws also work with electrolytes, also because I believe that we need to introduce the topic of surfactants, but I'm not sure

 

[Baluncore]

I haven't built the system because I'm still not sure of the values to use (voltage, current and frequency), otherwise the conductors I will use are iron rods like those used for antennas or metal objects or also electrolytes such as buckets of water with a mixture of sodium chloride to make it conductive. That is, mine are small experiments so there isn't a single conductor that I will use but many. I really don't need an image or photo in my opinion, I just need to know the formulas and ways to obtain the skin effect (far radiative field) for all cases of first and second species conductors (electrolytes) that's all

The technical term "skin effect" is irrelevant to this subject. The OP does not understand how currents flow through conductors or electrolytes. Electrochemical reactions take place on the wet surface of conductors, when current flows, so there is no need for an AC skin effect to move reactions to the surface.

Turning a wet landfill, into an electrolysis cell, will certainly be unpredictable. It will release reactive toxic gasses, such as chlorine, and solutions that contain toxic heavy metals, such as cadmium.

There is no "best" frequency range. Use DC.

 

[Sibilo]

The technical term "skin effect" is irrelevant to this subject. The OP does not understand how currents flow through conductors or electrolytes. Electrochemical reactions take place on the wet surface of conductors, when current flows, so there is no need for an AC skin effect to move reactions to the surface.

Turning a wet landfill, into an electrolysis cell, will certainly be unpredictable. It will release reactive toxic gasses, such as chlorine, and solutions that contain toxic heavy metals, such as cadmium.

There is no "best" frequency range. Use DC.

I'm sorry, I didn't understand what you mean when you say that electrochemical reactions take place on the wet surface of a conductor, in what sense? if you talk about electrolytes, I mean any conductive liquid, and in this case a bucket full of conductive water, in which by bringing the electrodes close to the surface of the water the current flows on the surface

 

[Baluncore]

I mean any conductive liquid, ...

Such as liquid mercury or molten metal?

... , and in this case a bucket full of conductive water, in which by bringing the electrodes close to the surface of the water the current flows on the surface

Which water surface with what? Across the boundary between the conductor and the electrolyte?
Or along the conductor surface, parallel to and within the conductor, but not along the electrolyte boundary equipotential contact with the conductor?

The conductive electrodes must be in contact with the electrolyte for an electron or ionic current to flow. If you place conductive electrodes on the surface of an electrolyte solution, an ionic current will flow deep through the volume of the solution. Ions move both ways through the liquid electrolyte, while electrons move through the conductive metal electrode. The ionic current flows through the bulk of the liquid, not along its external surface.

It is only where the electron current that flows in the conductor, is converted to an ionic current flowing in the electrolyte, that electrochemical reactions take place between the conductor and the electrolyte.

The EM skin effect is only significant in materials that make excellent electrical conductors.

 

[sophiecentaur]

the current follows the path with less resistance

A point of information; this is not true. Current is shared between multiple paths and the proportion of each share. relates to the resistance (the inverse of the resistance) of each path. This is very relevant to how anything you build will perform.

I really don't need an image or photo in my opinion,

You certainly do need one if you want to make any sense to us. I would go as far as to say that. if you can't draw your plan then you could never build your experiment.

 

[Sibilo]

Such as liquid mercury or molten metal?

Which water surface with what? Across the boundary between the conductor and the electrolyte?
Or along the conductor surface, parallel to and within the conductor, but not along the electrolyte boundary equipotential contact with the conductor?

The conductive electrodes must be in contact with the electrolyte for an electron or ionic current to flow. If you place conductive electrodes on the surface of an electrolyte solution, an ionic current will flow deep through the volume of the solution. Ions move both ways through the liquid electrolyte, while electrons move through the conductive metal electrode. The ionic current flows through the bulk of the liquid, not along its external surface.

It is only where the electron current that flows in the conductor, is converted to an ionic current flowing in the electrolyte, that electrochemical reactions take place between the conductor and the electrolyte.

The EM skin effect is only significant in materials that make excellent electrical conductors.

Yes, you said it right, in fact in electrolytes we are talking not about electronic conduction but about the migration of ions. Furthermore, I didn't know that the skin effect doesn't work in electrolytes and therefore there is no conduction on the surface, this puts me in difficulty. I have to place the conductive electrodes in contact with the surface of the electrolyte liquid, without going deep but just touching it. furthermore I cannot use a DC because in this case I would start a chemical reaction, electrolysis. so now considering the question of electrolytes, how can I make the current flow on the surface? or more generally, how can I make the current spread as much as possible throughout the entire volume of the electrolyte, therefore also in depth?

 

[Baluncore]

... how can I make the current flow on the surface?

Use a thin sheet of electrolyte, maybe between two glass plates, with electrodes at opposite edges between the plates.

How can you have an AC or DC current flow, without a chemical reaction at the electrode-electrolyte contact ?

You are wasting our time by not explaining what you are actually trying to achieve.

 

[berkeman]

You are wasting our time by not explaining what you are actually trying to achieve.

Yeah, agreed. OP is now on a short leash in this thread...

 

[Sibilo]

Use a thin sheet of electrolyte, maybe between two glass plates, with electrodes at opposite edges between the plates.

How can you have an AC or DC current flow, without a chemical reaction at the electrode-electrolyte contact ?

You are wasting our time by not explaining what you are actually trying to achieve.

ok gentlemen I will do some tests for each object I use. no but I'm not wasting your time, as I already said, these are small experiments that I want to do out of curiosity, so maybe I'll do some tests and see what happens.