Using an inverter to measure magnetic fields

A toroidal core may be used with an inverter circuit to measure magnetic fields in the .8 to 80,000 A/m (.01 to 1.0 KOe) range. The sensor core may be the inverter transformer itself or may be coupled to a nonsaturating inverter transformer. The sensor is most sensitive to fields parallel to the plane of the sensor and the sensitivity is greatest for a core biased to near saturation. An empirical expression for the demagnetization factor is used in calculating the ambient field required to saturate the sensor core, making it possible to calculate the range of fields for which a given core could be used as a sensor.