Electric charge flow in AC and DC

In summary: Okay, so that makes sense.Now for the third part." As electron in motion it proceed magnetic field." . Could you explain a little further?I think what you're saying is that the electric field pushes the electrons along, and the magnetic field helps them move in a particular direction. Sort of like how a magnet will hold a metal object in place.The fourth part, which is "The energy transfers via electromagnetic field, specifically it is photon ." . Do you mean that the energy is actually transferred as photons?Yes, that's right. photons are the particles that carry the energy in an electromagnetic field.
  • #1
Nihad Nazmul
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Can I say that energy transmitted in DC by electrons flow like ants walking align and in AC by electron vibration like water wave ?
 
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  • #2
No, because it isn't true. In both AC and DC the energy is transferred through the electromagnetic field. Current flow in a DC circuit is vaguely like ants marching in a line, but even that technically isn't accurate.

Try the following article. It's a little advanced, so don't worry if some of it doesn't make a lot of sense.
http://www2.warwick.ac.uk/fac/sci/physics/current/teach/module_home/px263/lectures/sefton.pdf
 
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  • #3
ImageUploadedByPhysics Forums1425236054.813674.jpg

From my understanding Direct current and alternating current only flow differently. The protons neutrons and electrons are in the same order. Direct-current is a continuous flow. Alternating current alternates from positive to negative.
 
  • #4
Electrons wiz about in random directions due to them having thermal energy.
In a DC circuit there is a drift super imposed on this random motion.
In an AC circuit the super imposed drift is first one way then the other.

If I remember correctly..
Typical thermal velocity is order 105m/S
Typical drift velocity is order 10-5 m/S

It might be a surprise that electrons take a long time to drift any significant distance. It's order cm per hour depending on the current.
 
  • #5
Nihad Nazmul said:
Can I say that energy transmitted in DC by electrons flow like ants walking align and in AC by electron vibration like water wave ?
Pictorial models of something as complicated as Electricity will just manage to confuse you. There is no short cut to understanding Electricity. One thing I can tell you is that using electrons when you want to describe what goes on in circuits is worse than unnecessary. Going back a few decades, schools taught electricity without introducing electrons (despite the fact that it was know how they are 'involved'; that is night here nor there.) We had no trouble in our electrical learning. Most of the electrical devices that you use were designed without using 'electrons' in the analysis. That goes for generators, radio antennas and motors, to name but three)
 
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  • #6
I agree. About the only time you need worry what the electrons are doing is when you are trying to understand the inner workings of semiconductors. You don't usually need worry about that stuff to actually use them.
 
  • #7
I just can't understand how anyone can be telling the OP (and millions of others) information that results with the words in that post. It isn't his/her fault - it just makes life harder for students these days when they have to undo such ideas for themselves.
 
  • #8
Drakkith said:
In both AC and DC the energy is transferred through the electromagnetic field.

Thank you. I think now I have a clear view of electricity. Let's set a conclusion,
1. Electric current is caused for potential difference.
2.Potential difference push electric field and electric field pile up the electrons.
3. As electron in motion it proceed magnetic field.
4. The energy transfers via electromagnetic field, specifically it is photon . As photon provide the convulse to electrons speed remains about 0.8c-0.9c and electrons gain drift velocity.
But I couldn't specify one thing that why electrons and current ( flow of electromagnetic field) flow inverse ? Perhaps I've got a reason . That direction of electric field and its push that means force is inverse, the equation F=(-e)E is the precision.
Are my decisions right? Please confirm me .
 
  • #9
No, it looks like you've gotten everything mixed up and I don't even know where to begin to help you. Any ideas, Sophiecentaur?

Edit: I'm having a little trouble understanding you, so you may have a few things correct but just didn't word them correctly.
 
  • #10
Okay, let's conclude individually . My first decision is 'Electric current is caused for potential difference' . As electric field is involved with Potential difference I think I can tell that . There is also an equation, V=Ed . At first confirm this?
 
  • #11
Do you mean, 'caused by a potential difference'?
 
  • #12
Yes.
 
  • #13
Okay, then yes, current flow is caused by applying a voltage (potential difference).
 
  • #14
Now,second one." Potential difference push electric field and electric field pile up the electrons" . I said that because there is an equation, F=(-e)*[V/d] . I've got the decision as a answer of this question "Why electric field will pile up the electrons ? " . Isn't it the real deal?
 
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  • #15
The potential difference is the result of an electric field, not the other way around. The electrons 'pile up' due to this electric field. Note that potential difference is measured in units of electric potential, which is defined as: the amount of electric potential energy that a unitary point electric charge would have if located at any point of space, and is equal to the work done by an electric field in carrying a unit positive charge from infinity to that point. (Full article here: http://en.wikipedia.org/wiki/Electric_potential)

This just means that voltage, also known as potential difference, is a measure of the potential energy of a charge between two points in an applied electric field. This could be anything from a single particle in a vacuum under the influence of an electric field, to a complicated circuit with multiple power supplies and loads.
 
  • #16
So electric field pile up the electrons by electric force[ E=F/(-e) ]. Third decision was " As electron in motion it proceed magnetic field ". This one maybe right, because without motion magnetic field can't manifest itself. But , it also may true that without electron only for motion of electric field magnetic field can be revealed.
 
  • #17
If by that you mean that a moving charge creates a magnetic field, yes. I thought you meant that 'an electron in motion is preceded by a magnetic field', which doesn't make any sense.
 
  • #18
I exactly meant that . Now, last one " The energy transfers via electromagnetic field, specifically it is photon . As photon provide the convulse to electrons speed remains about 0.8c-0.9c and electrons gain drift velocity." I've already tried to clear this one . What do you say?
 
  • #19
I'd forget you ever heard the word 'photon' for now. It's only going to confuse you. It is utterly unnecessary to understanding energy transfer in electronic circuits and the actual theory of mediating particles is so complicated that you don't have a chance of understanding it in any detail at this time. (Heck, neither do I) Energy transfer in electronic circuits is easily covered by classical electromagnetic theory.
 
  • #20
I will never ever use the word "photon" rather electromagnetic field. Okay, now come to my problem "I couldn't specify one thing that why electrons and current ( flow of electromagnetic field) flow inverse ? Perhaps I've got a reason . That direction of electric field and its push that means force is inverse, the equation F=(-e)E is the precision. " There may have more reason for this .
 
  • #21
In an AC circuit, the current flows in alternating directions because the polarity of the voltage alternates as well. That's it.

Also, just to be clear, the flow of current is not the same thing as the transfer of energy via an EM field. The EM field doesn't even flow.
 
  • #22
Then what means by flow of current? Flow of charge per time?
 
  • #23
Yes! That is exactly what amperage (the unit of current) is measuring! The number of charges flowing past a point per second.
 
  • #24
Okay. Which charge flow Is the current? Answer is electron . Then why it is reverse electron ?
 
  • #25
I don't understand what you mean by 'reverse electron'.
 
  • #26
Direction of current flow is reverse to the direction of electron's flow .
 
  • #27
Are you talking about what is known as 'conventional current' where current flow is envisioned as positive charges flowing?
 
  • #28
Drakkith said:
Are you talking about what is known as 'conventional current' where current flow is envisioned as positive charges flowing?
Yes.
 
  • #29
It turns out that modeling current as positive charges gives you the exact same predictions as using negative charges, provided that the direction of current flow is opposite in each case. Prior to the discovery of the electron, current was modeled as positive charges flowing through a circuit. It's stuck around since then.
 
  • #30
I knew these before . But what is the role of electromagnetic field?
 
  • #31
What do you mean?
 
  • #32
Maybe I messed up energy and current together. Now I have the conclusion. Glowing a light bulb current has no role and it is done by electromagnetic magnetic field .
 
  • #33
Nihad Nazmul said:
Maybe I messed up energy and current together. Now I have the conclusion. Glowing a light bulb current has no role and it is done by electromagnetic magnetic field .

As with most things, it isn't quite that simple and I'm afraid that we've reached the limit of my knowledge in this area. Just consider that power, which is energy transferred over time, can be find by: P=VI, where P is power, V is voltage, and I is current. In other words, the amount of energy transferred over time is equal to the product of the voltage times the current flow. So I'm not sure I'd say that current has no role in causing a light bulb to glow.

I hope I haven't managed to lead you astray. Perhaps someone with more knowledge than myself can take over from here.
 
  • #34
Nihad Nazmul said:
Maybe I messed up energy and current together. Now I have the conclusion. Glowing a light bulb current has no role and it is done by electromagnetic magnetic field .

The filament heats up because electrons collide with metal ions. So the current is important.
 
  • #35
Electromagnetic field transmits energy. As electromagnetic field acts in quanta that means photon. Then glowing up of bulb filament easily can be explained. Filament produce radiation when photon collide with electron (in filament orbital) and electron completes the Bohr's quantum jump . In glowing the bulb maybe current doesn't interfere . But electromagnetic field depends on current that means flow of electron. So, the more electron the more work therefore the more energy.Note that I may have mistakes.
 
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<h2>1. What is the difference between AC and DC?</h2><p>AC (alternating current) is a type of electrical current that periodically changes direction, while DC (direct current) flows in only one direction. AC is commonly used in household appliances and power grids, while DC is often used in smaller electronics such as batteries.</p><h2>2. How does electric charge flow in AC and DC circuits?</h2><p>In AC circuits, the flow of electric charge changes direction periodically, causing the current to alternate between positive and negative values. In DC circuits, the flow of electric charge remains in one direction, from the positive terminal to the negative terminal.</p><h2>3. What is the frequency of AC current?</h2><p>The frequency of AC current is the number of times the current changes direction in one second, measured in Hertz (Hz). In most countries, the standard frequency for AC power is 50 or 60 Hz.</p><h2>4. How is AC current converted to DC current?</h2><p>AC current can be converted to DC current using a device called a rectifier. This device uses diodes to convert the alternating current into a direct current by allowing current to flow in only one direction.</p><h2>5. What are the advantages and disadvantages of AC and DC?</h2><p>AC has the advantage of being able to travel long distances without significant loss of energy, making it ideal for powering large electrical grids. DC, on the other hand, is more efficient for smaller electronic devices and can be easily converted from AC. However, DC requires more complex circuitry to convert and is not suitable for long-distance transmission.</p>

1. What is the difference between AC and DC?

AC (alternating current) is a type of electrical current that periodically changes direction, while DC (direct current) flows in only one direction. AC is commonly used in household appliances and power grids, while DC is often used in smaller electronics such as batteries.

2. How does electric charge flow in AC and DC circuits?

In AC circuits, the flow of electric charge changes direction periodically, causing the current to alternate between positive and negative values. In DC circuits, the flow of electric charge remains in one direction, from the positive terminal to the negative terminal.

3. What is the frequency of AC current?

The frequency of AC current is the number of times the current changes direction in one second, measured in Hertz (Hz). In most countries, the standard frequency for AC power is 50 or 60 Hz.

4. How is AC current converted to DC current?

AC current can be converted to DC current using a device called a rectifier. This device uses diodes to convert the alternating current into a direct current by allowing current to flow in only one direction.

5. What are the advantages and disadvantages of AC and DC?

AC has the advantage of being able to travel long distances without significant loss of energy, making it ideal for powering large electrical grids. DC, on the other hand, is more efficient for smaller electronic devices and can be easily converted from AC. However, DC requires more complex circuitry to convert and is not suitable for long-distance transmission.

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