Control a magnetic field

[jcheak]

Does anyone have any resource links on the internet that I can read about about how to control a magnetic field, perhaps even do an amateur experiment... It is a topic I am interested in but have not had much luck on the standard google search for "control magnetic field."

Thanks,

 

Jeff in Connecticut

[Klaynos]

http://en.wikipedia.org/wiki/Electromagnet

http://www.howstuffworks.com/electromagnet.htm

[tvp45]

When you say "control", what do you mean? Do you want to create, to achieve a certain gradient, to shield, etc??

[jcheak]

Well, yes, I want to control the shape of a magnetic field to see ferrofluid move on top.

[Klaynos]

you'd need an array of electromagnets then

[antimatter]

What do you mean by array?

As in; arranged in a specific pattern?

[Klaynos]

What do you mean by array?

As in; arranged in a specific pattern?

 

Yeah, just some periodic group... a grid of 4 is teh simplest array:

 

x x

x x

 

But you can have any structure.... If you have an array the tigher packed and the smaller the nodes (electromagnets) the more you can control the shape of the field....

[alan2here]

Useful reply time.

 

If you do not understand electronics (like me) transistors and resistors and how to make circuits that do different things (and possibly also a level of mathematics to back it up) and have never attempted to purchase wire or make coils and don't know how you would do so then you can't do what you are imagining.

 

Yep pritty sucky but true. I have no idea how you would get started learning this stuff (don't all point at wiki articles he and many of us probably wont be able to follow).

[antimatter]

Find a book about it.

I realized that what I was learning in class wasn't enough for me, so I went out and found a book that filled me in on most of the concepts.

I can't remember off the top of my head the name of this book, but it was a textbook from about 10 years ago...

[Klaynos]

Another less controlable method would be if you had an array of normal magnets, and you moved them closer and further away from the working surface....

[jcheak]

Ok, so good idea on the array of electromagnets. This brings up yet another question. I take it with an electromagnet you can change the shape of the magnetic field by changing the current that you push through the magnet correct?

 

If this is true then nothing should be able to stop me from creating an shape I like right? (ie. a cube and then turn the cube into a sphere)

[alan2here]

There are certain rules about what happens, play with some strong non-electro magnets and you will see what I mean. I think given complex enough rules about how to power the grid at the bottom then you would be correct or at least partly correct.

[Klaynos]

Creating 3D "shapes" will be much harder as the fields do not have sharpe edges but drop off with distance... you would be able to create 2D shapes on the plane, although the resolution of them depends greatly on the array...

[Robin07]

If you stack Nib disks, one on top of the other as the disks get successivley smaller as well as stacking more on the under side, making sure that they all line up on the same axis you will have made a sphere with circular steps in it, top positive and the opposite pole on the other end. Now you'll have a very very very much stronger flux filed than what you would have imagined. PLEASE BE CAREFULL, wear eye protection and be ready for a pinch or blood blisters. Then, take your assembley and dip it into the smallest ferrous granuals as possible, remove and your done. Try stacking various configurations to come up with what your looking for, Good luck. I haven't been able to take mine apart, it's that strong. My original intention for this was to make an exterior magnetic field, It was succesfull.

 

Robin07

Nullflux8ight