A conductor apparatus, comprising: a conductive structure operative to conduct current along a longitudinal direction, the conductive structure comprising an outer periphery extending between first and second longitudinal ends (111, 112); and a magnetometer, comprising: an array of at least two magnetic sensors located on a single integrated circuit at least partially within the outer periphery of the conductive structure,wherein the magnetic sensors include a circular sensor having an associated circular sensing direction transverse to the longitudinal direction of the conductive structure, and wherein the circular sensor surrounds a point along a first side of the magnetometer transverse to the longitudinal direction of the conductive structure, wherein the circular sensor is a first circular magnetic sensor and the magnetometer further includes a second circular magnetic sensor, the first and second circular sensors individually having an associated circular sensing direction transverse to the longitudinal direction of the conductive structure and individually surrounding the point along the first side of the magnetometer, wherein the first and second circular sensors are concentric of different diameters, a sensor interface circuit operatively coupled to the magnetic sensors to generate at least one output signal or value representing longitudinal current flow in the conductive structure based at least partially on at least one signal from the magnetic sensors, and a plurality of wires electrically connected to the sensor interface circuit and extending outside the outer periphery of the conductive structure. a conductive structure operative to conduct current along a longitudinal direction, the conductive structure comprising an outer periphery extending between first and second longitudinal ends (111, 112); and a magnetometer, comprising: an array of at least two magnetic sensors located on a single integrated circuit at least partially within the outer periphery of the conductive structure,wherein the magnetic sensors include a circular sensor having an associated circular sensing direction transverse to the longitudinal direction of the conductive structure, and wherein the circular sensor surrounds a point along a first side of the magnetometer transverse to the longitudinal direction of the conductive structure, wherein the circular sensor is a first circular magnetic sensor and the magnetometer further includes a second circular magnetic sensor, the first and second circular sensors individually having an associated circular sensing direction transverse to the longitudinal direction of the conductive structure and individually surrounding the point along the first side of the magnetometer, wherein the first and second circular sensors are concentric of different diameters, a sensor interface circuit operatively coupled to the magnetic sensors to generate at least one output signal or value representing longitudinal current flow in the conductive structure based at least partially on at least one signal from the magnetic sensors, and a plurality of wires electrically connected to the sensor interface circuit and extending outside the outer periphery of the conductive structure. an array of at least two magnetic sensors located on a single integrated circuit at least partially within the outer periphery of the conductive structure,wherein the magnetic sensors include a circular sensor having an associated circular sensing direction transverse to the longitudinal direction of the conductive structure, and wherein the circular sensor surrounds a point along a first side of the magnetometer transverse to the longitudinal direction of the conductive structure, wherein the circular sensor is a first circular magnetic sensor and the magnetometer further includes a second circular magnetic sensor, the first and second circular sensors individually having an associated circular sensing direction transverse to the longitudinal direction of the conductive structure and individually surrounding the point along the first side of the magnetometer, wherein the first and second circular sensors are concentric of different diameters, a sensor interface circuit operatively coupled to the magnetic sensors to generate at least one output signal or value representing longitudinal current flow in the conductive structure based at least partially on at least one signal from the magnetic sensors, and a plurality of wires electrically connected to the sensor interface circuit and extending outside the outer periphery of the conductive structure.