Three different models of a magnetic dipole, viz., a uniformly magnetised sphere, a circular current
loop and a pair of fictitious magnetic charges, have been systematically analysed within the
formalism based on the vector potential of the magnetic field. The expressions of the potentials and
magnetic fields produced by each dipole model have been obtained. A computer code has been put
forward in order to visualise magnetic field lines for different dipole models. It has been shown
that the magnetic field outside the uniformly magnetised sphere coincides with that of a point
dipole. The other two models give considerably different results at distances small or intermediate
in comparison with the dipole size.