# I have a problem, maybe you can help me.....

From: Carsten Brosda (brosda@glion.ch)
Date: Thu Mar 02 2000 - 11:00:26 PST

Hello, snack team!
I have a slight problem concerning electro-magnetism....hopefully you can give me an advise. I am a student in Switzerland and I need to create an electromagnetic field which I can switch on and off. I have a slight Idea how this could work, but the problem is, that the current has to come from a battery because it has to be portable. So I might have to include a transformer or any other equipment to get the sufficient amount of current for the field. This problem goes beyond my physical knowledge even if I am always trying to keep on improving it.
Another problem is, that the field has to cover a surface of a circle with a radius of 30 cm. The intensity/ force has to be nearly the same, if you have a weight of 100 gramm would hang down from it. The contact area between the surface and the 100 gramm weight would be around a circle with a radius of 3 to 4 cm. the field would have to be able to hold around 10 to 12 times this little circles on the big surface. For me this sounds totally impossible, like a kind of science fiction, because the whole thing should not have more weight than 1 Kg!!!
I thought already about a small strong Lithium battery with a transformer as surce of the current, and to generate the field about a "thin" metall wire, which is rolled like a flat spiral to cover the surface of the big 30 cm radius circle.
I know this sounds like the dream of a beginner, but maybe you can think about a possibility to make it work. I would be the most happy guy on the planet if you would have a solution for me....