What is it about?
Measurements of magnetic properties of soft magnetic materials by using Epstein frame, single-sheet tester or toroidal sample are prescribed by national and international standards. These methods define that the primary current is to be measured by a shunt resistor. This paper describes shows that the variation of the value of this sensor has no discernible influence on the measured values.
Why is it important?
This is one of the very few publications which performs analysis of this kind of measurement, even though it is fundamental to the standardised methods. The accuracy of magnetic measurements is affected by the accuracy to which the value of shunt resistance is measured, but not the value itself. However, there are secondary effects (like for example range changing) which might come into play, and adversely affect the measurements.