Patent ID: 9103653
Filing Date: 2015-08-11
Classification: G01B,G01R

Abstract:
1. A method for performing a non-contact resistivity measurement of a sheet of material to be measured, the method comprising: moving, with a motor, a magnet in one of a linear direction and a rotational direction; determining, with a power measuring device, a first power value used by the motor in moving the magnet when in proximity to the sheet of material, and measuring a second power value used by the motor in moving the magnet when not in proximity to the sheet of material; and determining, with a computing device, a difference between the first power value and the second power value, wherein the first power value is greater than the second power value due to a magnetic braking effect from an induced eddy current in the sheet by motion of the magnet in proximity to the sheet of material, the computing device using the difference between the first and second power values to compute the resistivity of the sheet of material; wherein the computing device uses a known distance between the magnet and the sheet of material to compute the resistivity of the sheet of material, and computes the resistivity, σ S , of the sheet of material in accordance with the expression: with α=3μ wherein P