Abstract
Measurements of magnetic properties of toroidal samples of magnetically soft materials are defined by the group of international standards IEC 60404.
These standards do not specify the actual value of the shunt resistor, but for instance just the fact that it should be ``non-inductive''. This study provides more information on the topic of selection of shunt resistance, which is crucial for many studies of magnetic measurements.
It was found that the resistance value of a shunt resistor has no direct effect on the measurement results of magnetic properties. The quality of calibration of the value does have a direct effect, but not the value itself and it could have any value from 0.1 Ω to 10.0 Ω (as investigated).
Care must be taken so that additional device-specific effects are not induced in the measurement equipment (e.g. reduced accuracy at the lowest or highest input ranges). The value of the shunt resistor should be such that the voltage drop across it would coincide with the most accurate input range of the voltmeter or data acquisition device.