The paper presents a modified version of the T.E.A.M. Problem No. 32 of the Compumag Society. The original problem is a measurement arrangement to study the magnetic flux density distribution inside an EI ferrite core. A finite element simulation of the device in the frame of COMSOL Multiphysics using the A -formulation has been worked out. First, the device has been realized, and a LabVIEW program has been implemented to measure the waveform of the voltage of B-coils. The geometry and the solution of the problem have been implemented in the frame of COMSOL Multiphysics, to calculate magnetic flux density at the points, where B-coils are on the core.