# Illustration B-field along the z-axis (graph) of a current-carrying ring

Magnetic field vs. position graph of an annular current-carrying conductor loop oriented perpendicular to the z-axis, with the $$z$$ axis passing through the center of the ring. The graph shows the shape of the magnetic field $$\class{violet}{\boldsymbol{B}}$$ along the $$z$$ axis.
Exactly in the center of the ring the magnetic field has a maximum. The magnetic field decreases along the z-axis in both directions as follows:$$\class{violet}{\boldsymbol{B}}(z) ~=~ \frac{\mu_0 \, I }{ 2 } \, \frac{R^2}{ (R^2 ~+~ z^2)^{\frac{3}{2}} }$$where $$I$$ is the current through the ring and $$R$$ is the radius of the ring.