# Building an electro magnet

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Tags: building, electro, magnet
 P: 39 Hey guys.. I trying to build an magnet which can pull an object with 5N.. I am using S37 as my the iron for my horseshoe magnet, And been using this formula to convert Newtonian Force to magnetic force $\vec{F}=\frac{B}{µ0}*A$ A= cross sectional area = 0,002*1/100 M^2 B = Magnetic Force µ0(permeability in vacuum) = 4$\pi$*10^-17 B_gap(x) =$\frac{µ0*I*N}{\frac{l_j}{µj}+2x}$ l_j: the length of horseshoe = 2 CM µj: permeability of Steel37.. Can't find it using google.. :( x: airgap distance between each legs and the materiel it should attract. = 0,002m I am using 1 A, I tested my calctulation with 3N, which using my calculation says that i need 600 windings, but i seem to extreme.. The reason why i think this is not true is because 600 winding => 2 (0.002 + 0.01)*600 M copper wire=> R=0,079 ohm => V =0,079V.. Is it too extreme?
 P: 39 My caluculation is kinda simple.. Assume that the magnetic force from the iron core is the same as the one in the gap. I know that I need the magnet to pull 5N Which means that F=$\frac{b}{µ0}*A$ Where A =0,002*1/100 <=> 5 =$\frac{b}{µ0}*A$ <=> B =3.14159*10^-11 Then i solve N using the other equation and then i get 1001 winding.