Sensor for saturation core magnetometer for alternating magnetic fields

摘要

The sensor comprises two rod-shaped sensors arranged parallel to the field to be measured. The sensors are magnetically connected to each other by cross bridges so as to provide a closed magnetising path. The core material is periodically pre-magnetised in the area of the path. Cross section tapers are arranged in the two longitudinal bridges of the premagnetised area to increase the flux density in the core region. Thus measurable, temporal shifts in the zero crossing point of the flux density in the core are generated which are proportional to externally applied magnetic fields in the longitudinal direction. The arrangement provides an electronic regulation of the amplitude of the current generating the pre-magnetising field using a pulse width method. The zero crossing times of this current are combined to provide the flux density in the core by sampling two equal voltages of different polarities. These voltages are averaged to provide a signal to stabilise the operating point independently of the external field.