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Caen, France

Maria T.,GREYC UMR 6072 | Gilles A.,GREYC UMR 6072 | Gilles A.,University of Caen Lower Normandy | Didier R.,GREYC UMR 6072 | And 3 more authors.
Sensors and Transducers | Year: 2012

A theoretical and experimental comparison of optimized search coils based magnetometers, operating either in the Flux mode or in the classical Lenz-Faraday mode, is presented. The improvements provided by the Flux mode in terms of bandwidth and measuring range of the sensor are detailed. Theory, SPICE model and measurements are in good agreement. The spatial resolution of the sensor is studied which is an important parameter for applications in non destructive evaluation. A general expression of the magnetic sensitivity of search coils sensors is derived. Solutions are proposed to design magnetometers with reduced weight and volume without degrading the magnetic sensitivity. An original differential search coil based magnetometer, made of coupled coils, operating in flux mode and connected to a differential transimpedance amplifier is proposed. It is shown that this structure is better in terms of volume occupancy than magnetometers using two separated coils without any degradation in magnetic sensitivity. Experimental results are in good agreement with calculations. © 2012 IFSA. Source


Allegre G.,GREYC UMR 6072 | Timofeeva M.,GREYC UMR 6072 | Thomas J.,National Engineering School of Caen | Flament S.,GREYC UMR 6072 | Robbes D.,GREYC UMR 6072
2013 22nd International Conference on Noise and Fluctuations, ICNF 2013 | Year: 2013

This contribution presents, in a reverse engineering like approach, the noise measurements and analysis of two commercially available magneto-resistive currents sensors respectively based on GMR (NVE Inc.) and AMR (SENSITEC GmbH) Wheatstone bridges. Comparison is done with the ultimate aim of designing low noise current conditioners for mini search coils based, magnetometers with galvanic insulation useful for further developments. © 2013 IEEE. Source


Robbes D.,GREYC UMR 6072 | Jorel C.,GREYC UMR 6072 | Olivier E.,GREYC UMR 6072 | Mechin L.,GREYC UMR 6072 | And 4 more authors.
IEEE SENSORS 2013 - Proceedings | Year: 2013

Ways to sense electric field using PZT capacitors are investigated. Duality rules a priori apply to material physics, linking polarization to magnetization properties, i.e. D(E) to B(H) curves, but no real electrical flux gate or charge gate does exist which would be the dual of the common flux gate magnetometer. The Landau - Khalatnikov equations are applied to ferroelectric materials subjected to both a DC and an AC pumping signal. They are solved to get the model of the PZT capacitors dynamics. They are experimentally investigated using the Sawyer Tower method. A second harmonic detection is a way to extract the DC excitation. © 2013 IEEE. Source

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