• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

physics question involving inducted EMF?

Ika

Ika

Lifer
I've been trying to google the answer, but to no avail. Most AC power cords are made with two wires, side-by-side, running parallel to each other over the length of the cord. Apparently they're made this way due to some factor of EMF (probably induced), but I don't really understand it. Anyone?

THE FULL QUESTION:

Most A.C. power cords are made with two wires, side-by-side and molded in plastic, parallel to each other over the length of the cord. Based on your understanding of EMF, why are power cords made this way?

EDIT: read this post for more info
http://forums.anandtech.com/showthread.php?t=2064076#29
 
Last edited:
electric&
 
Aflac said:
I've been trying to google the answer, but to no avail. Most AC power cords are made with two wires, side-by-side, running parallel to each other over the length of the cord. Apparently they're made this way due to some factor of EMF (probably induced), but I don't really understand it. Anyone?
Click to expand...

Uh, what? lol

You don't have a complete circuit with only 1 wire. It has nothing to do with EMF.
 
Eli said:
Uh, what? lol

You don't have a complete circuit with only 1 wire. It has nothing to do with EMF.
Click to expand...

If that were the case it would be a really stupid question to ask on an induced EMF physics lab. Is that true even in an AC circuit? I thought because of the alternation the single conductor would suffice just fine.
 
Aflac said:
My understanding of the question is that it infers that the reason for the two conductors isn't because the current goes forward and back, but it has something to do with induced EMF. Because it's AC, a single conductor would be sufficient to provide power to something... right? I don't understand AC circuits very well...
Click to expand...

No. You still need a 0V reference(neutral, or ground). The circuit wouldn't be complete otherwise.

It's no different than DC in this regard.

Edit: My wording isn't correct here, as you don't technically need a neutral/ground with AC. For example, the neutral isn't used with an appliance like your 240V dryer.
 
Last edited:
Aflac said:
My understanding of the question is that it infers that the reason for the two conductors isn't because the current goes forward and back, but it has something to do with induced EMF. Because it's AC, a single conductor would be sufficient to provide power to something... right? I don't understand AC circuits very well...
Click to expand...

The term circuit implies both a source and a return path.
 
Eli said:
No. You still need a 0V reference(neutral, or ground). The circuit wouldn't be complete.

It's no different than DC in this regard.
Click to expand...

But but but that's too simple to be the correct answer... there really isn't anything here that has to do with induced EMF? 🙁
 
Aflac said:
My understanding of the question is that it infers that the reason for the two conductors isn't because the current goes forward and back, but it has something to do with induced EMF. Because it's AC, a single conductor would be sufficient to provide power to something... right? I don't understand AC circuits very well...
Click to expand...

You have no current in an open circuit. It's no different than with DC.

You do not need a ground with AC, maybe that's where you're getting confused.

If the manufacturer were concerned with EMF they'd twist the wire or do coaxial cabling.

The wires are probably parallel because it's cheaper to make them that way.
 
Last edited:
i think he thinks you can use ground for the other wire
like one hot wire and then just ground everything so that is the 'other wire' D:
 
FoBoT said:
i think he thinks you can use ground for the other wire
like one hot wire and then just ground everything so that is the 'other wire' D:
Click to expand...

That's what I was thinking. If you had a fully metal house with metal furnature, you could just place your metal lamp on the table and just hook the 1 hot wire up to the outlet. 🙂 Just please don't try to pick up the lamp... 😛
 
CADsortaGUY said:
That's what I was thinking. If you had a fully metal house with metal furnature, you could just place your metal lamp on the table and just hook the 1 hot wire up to the outlet. 🙂 Just please don't try to pick up the lamp... 😛
Click to expand...

picking up the lamp = cheap dimmer! :awe:
 
Aflac said:
My understanding of the question is that it infers that the reason for the two conductors isn't because the current goes forward and back, but it has something to do with induced EMF. Because it's AC, a single conductor would be sufficient to provide power to something... right? I don't understand AC circuits very well...
Click to expand...

lmao! It's a shame that physics isn't required in high school. Errr, uhhh, wait a second... I'm pretty sure this stuff is covered in 5th grade in NY. Ever hear of a complete circuit? Perhaps you're confused by automobiles where the chassis is used as a conductor.
 
You must log in or register to reply here.

TRENDING THREADS

Back
Top