The amplitude sensitive eddy current method according to DIN EN ISO 2360 is, like the magnetic induction method, a contact measurement method.
This procedure is used for the measurement of electrically non-conductive and non-magnetic coatings on a non-ferro-magnetic, electrically charged base material (NF metal). How does the amplitude sensitive eddy current method work? An exciter current is first used to generate a high frequency magnetic field. This results in conductive, non-magnetic base material eddy currents. The strength of these eddy currents is dependent on the distance or coat thickness between the measuring probe and the base material. The measurement signal created by the eddy current is then transformed into the precise coat thickness value in a special measuring device, via the probe characteristics – the functional interrelation between measurement signal and coat thickness.
The penetration depth of the field is determined by the conductivity of the base material and the frequency used.
DIN EN ISO 2360