Physical Science 6.8a - Electric Current and Magnetic Fields

From the Physical Science course by Derek Owens. An introduction to the magnetic fields caused by current flow through a wire. Distance learning classes are available at http://www.derekowens.com

Category:

Education

Tags:

• Physical Science
• electric current
• magnetic fields
• magnetic field
• current
• magnet
• magnetic
• Derek Owens
• distance learning
• electromagnet
• electro magnet

[M1ST3RHYDE]

If l have a coil of wire wound in an upward helix around an iron bar & I wind an additional coil of wire back down (1,2,3 or more passes) would thereverse direction of the windings produce a stronger field or would it just decrease the strength? Thanks for any help.

[derekowens]

@M1ST3RHYDE It depends on how the wire was wrapped as go "back down". If the current continues to go around the core in the same direction, say, clockwise, then the additional coils will strengthen the field. But if the wire is wrapped so that the current goes around the core in the opposite direction, then the additional coils will weaken the field. If that doesn't clear it up, I'll have to make a video to *show* it. It's a little hard to type out the description. DO.

[idster7]

so you said that you use direction of positive current in the right hand rule. so, if positive current points one way, really, it is electrons pointing the other way, and a left hand rule could be used to describe the magnetic field in terms of electrons? is that right? thank you, mr. owens

[derekowens]

@idster7 Yes, that's right. If you think in terms of electron flow, then the left hand rule applies instead of the right hand rule.  This difference is, unfortunately, somewhat confusing, has been an endless source of confusion to physics students for the past century.

[ourtrashcans]

@derekowens Why don't we just follow the electric fields. Since there can be no magnetic field without an electric one. You jump right out of an electric flow into the magnetic result without explaining the electric result. This is exactly why everyone has been so confused for centuries.

[derekowens]

@ourtrashcans Oh, right, I see what you're saying, and that's a good point. The electric and magnetic fields really work together, but that's beyond the scope of this course. I would love to dig into that more, though, and make some videos on that also at some point. When I get some free time....

[mohamedamjadakram]

I'd like to thank you wholeheartedly for all your valuable contribution. I learn a lot from your videos and I am very grateful. THANK YOU SO MUCH!

[8644371]

BLEW MY MIND.

[MrHladysh]

this material that superconductors are made of, what is it? and how is there no electrical resistance?

[MsTightman]

can u explain what is ampere law and 2pir in equation of ampere law and then there is no 2pir in magnetic field due to soleniod . i am really confused

[Mentord]

I agree , pretty cool stuff

[reveresm]

man I like your drawing its pretty neat.

[RollingPages98]

cool

[RSPSpro1]

what program are you using to do this?

[ehtep]

Hi, I have a similar question to the last post but in regards to a (welder) transformer. Lets say I want to get an even lower output of the Secondary, but I’m only given the primary coils to do it on. The primary consists of 3 sets at 90-30-30 turns, Could I in theory have 90 turns in one direction, and 60 turns in the opposite direction

Would this reduce the output on the Secondary coil?

Would the primary draw more current wound this way or would it act like a choke drawing less current?

[M1ST3RHYDE]

@derekowens

Copy that.... & Thanks you.