Alternating Current Explained: How Does It Move Forward?

In summary, the direction of current in an alternating current (AC) changes constantly due to the changing electric field in the wire. This causes the electrons to move back and forth, creating the current that powers devices. DC current, on the other hand, has a continuous electric field that pushes the electrons forward, but they are constantly slowed down by collisions with atoms in the wire.
  • #1
PrincePhoenix
Gold Member
116
2
Can someone please explain how the current regularly changes direction after some time in alternating current? I mean if it changes direction, how does it move forward?
 
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  • #2
Hi there,

You have to understand that it is not necessarily a current like water flowing through a hose. In an electrical wire, the electrons are submitted to an electric field. In a DC current, the electric field is continous, and pushes the electron forward. But the electrons make direct hit with the atoms in the wire, therefore being constantly slowed down, to a few cm per hour.

In an AC current, the electric field changes direction constantly. The electrons present in your wire will therefore go back and forth, creating the current and the potential work done on the appliance. Therefore, you don't need it to move forward, since electrons are everywhere in the wire.

Hope this helps. Cheers
 
  • #3
Can you explain it a little simpler? Which electric field are you talking about, that is continuous and pushes electrons forward in DC?
 
  • #4
Hi there,

I'll try to give you simpler explanation.

To generate a current AC or DC, you need voltage. I'll keep with the copper wire example. A certain voltage is applied at both ends of your circuit. Voltage is just another way of saying that an electric field is created in the wire.

Remember that electrons, being electrically charged particles, will only react under the influence of an electric field.

Ok, so you have an electric field that forces your electrons to move. Fact is that the electrons in your wire are not coming from very far. They are taken right there on the spot, using the "free" electrons of copper atoms.

Now to make my story complete, it is the movement of electrons that will make the work in your device (mp3 player and so on). Therefore, whether the electrons are always pushed in the same direction, or whether they change direction, as long as they move.

Is this any clearer now?

Cheers
 
  • #5
Yeah. That made it a lot clearer. Thanks
 

1. What is alternating current (AC)?

Alternating current is a type of electrical current that periodically changes direction, unlike direct current (DC) which only flows in one direction.

2. How does alternating current move forward?

Alternating current moves forward by constantly changing direction, with the current flowing first in one direction and then in the opposite direction. This creates a back-and-forth motion that allows the current to travel through a circuit.

3. What is the difference between alternating current and direct current?

The main difference between alternating current and direct current is the direction of flow. Alternating current periodically changes direction, while direct current only flows in one direction. AC is also typically used for long-distance power transmission, while DC is commonly used for small electronic devices.

4. How is alternating current generated?

Alternating current is typically generated by an electrical generator, which uses mechanical energy to rotate a coil of wire within a magnetic field. This creates a flow of electrons, resulting in an alternating current.

5. What are the advantages of alternating current?

Alternating current has several advantages, including the ability to be easily converted to different voltages, making it ideal for long-distance power transmission. It also allows for the use of transformers, which are important for regulating voltage and reducing energy losses. Additionally, AC is more efficient for powering large devices and machinery.

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