Nano-teslameter for characterization of the fields emitted and received by wound electronic components.

A measuring bench has been built to churacferize the mogneficfield radiated by inducfors and fransformers used in switch mode power supplies which enfer a 10 cm wide cube. The frequency domain of interesf is 100 kHz IO MHz To compress relwanf data, the multipolar expansion is used and some special exfensions are infroduced Measuremenf of radial componenf induction, in a few fens of points regularly spaced on a sphere, leads io an accurate characferization of the whole externulfield by, at mosf, 15 scalarparameters. Field to measure is ofren below IO nT and several constraints restrict probe choice so a lock in amplifier is used to measure the very low volfage thaf results. Owing to a lot of care, the target is reached and inducfion is meusured accurately over the whole frequency range. Luckily, as soon us fhe emission of a component is known, its sensitivify to un externalfield is known too. Finally, measurements carried ouf on two industrial inductors are presented, leading to first conclusions regurding incidence of core shape andpenneability.