1. Sep 8, 2013

ZecronTech

On that site, it states that the Radius = the outer radius - the inner. It doesn't make sense. What happens when there is only one layer of coil and the outer radius (OR) is basically the inner radius (IR). That would create a larger magnetic field than if I had multiple layers of coils and the OR > IR which would then create a smaller one. I don't understand why.

2. Sep 8, 2013

Staff: Mentor

Where?
Even in that case, your cables have a finite width.

You can probably consider this equation in the limit r1 -> r2, and get a simpler equation for the case where the difference between both is not significant.

3. Sep 8, 2013

ZecronTech

In the equation where the denominator is 2(r2-r1). So I'm assuming that the more layers of coils you have, the greater r2-r1 is and therefore less magnetic fields. Which I don't get. I thought the more coils you have, the greater the magnetic field.

4. Sep 8, 2013

Staff: Mentor

Careful, the radii are used in the logarithms as well. It is not clear which effect will dominate if you don't calculate it.

"More coils" would also increase n (more windings) or I (more current), cancelling this effect. More coils give a higher field strength.

5. Sep 8, 2013

ZecronTech

Oh....Whoops. Thank you. I can't believe I forgot about that.