Alternating Current Explained: How Does It Move Forward?

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Discussion Overview

The discussion revolves around the nature of alternating current (AC) and how it differs from direct current (DC) in terms of electron movement and the role of electric fields. Participants explore the mechanics of current flow in electrical wires, particularly focusing on the implications of changing directions in AC.

Discussion Character

  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant asks how alternating current can move forward if it regularly changes direction.
  • Another participant explains that in AC, electrons oscillate back and forth due to a changing electric field, and they do not need to move in one direction to create current.
  • A request for a simpler explanation is made regarding the continuous electric field in DC that pushes electrons forward.
  • A further attempt to clarify indicates that voltage creates an electric field that influences electron movement, and that the electrons used in the circuit are "free" electrons from the copper atoms in the wire.
  • It is noted that the movement of electrons, regardless of direction, is what performs work in electrical devices.

Areas of Agreement / Disagreement

Participants generally agree on the basic principles of how AC and DC operate, but there is some variation in the clarity of explanations and understanding of the concepts involved.

Contextual Notes

Some assumptions about the nature of electric fields and electron behavior in different types of current may not be fully articulated, and the discussion does not resolve all aspects of how these concepts interrelate.

PrincePhoenix
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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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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
 
Can you explain it a little simpler? Which electric field are you talking about, that is continuous and pushes electrons forward in DC?
 
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
 
Yeah. That made it a lot clearer. Thanks
 

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