NORMALIZED PARAMETERS OF A MAGNETORESISTIVE SENSOR IN BRIDGE CIRCUITS

Magnetoresistive sensors are considered as part of bridge circuits for measuring magnetic field strength and electric current value. Normalized or relative expressions are introduced to change the resistance of the sensor and the measured bridge voltage to increase the information content of the regime to provide the possibility of comparing the regimes of different sensors. To justify these expressions, a geometric interpretation of the bridge regimes, which leads to hyperbolic straight line geometry and a cross ratio of four points, is given. Upon a change in the sensor resistance, the bridge regime is quantified by the value of the cross ratio of four samples (three characteristic values and the current or real value) of voltage and resistance. The cross ratio, as a dimensionless value, is taken as a normalized expression for the bridge voltage and sensor resistance. Moreover, the cross ratio value is an invariant for voltage and resistance. The proposed approach considers linear and nonlinear dependences of measured voltage on sensor resistance from general positions.

Magnetic field strength gradiometer

Measurements of magnetic field parameters are the basis of all magnetic measurements. Most methods of measuring magnetic field parameters are based on force (energy) interaction of magnetic field with macro- or microscopic currents and electromagnetic induction. The paper considers the possibility of constructing a magnetic field strength gradient meter based on the absolute helical instability of electron-hole plasma of a semiconductor sample. The functional scheme of the gradiometer and the results of experimental and theoretical studies of the sensitive element of the gradiometer are presented

Teslameter for magnetic field measurement in high voltage facilities

This paper presents a low-cost three-axis teslameter capable of measuring magnetic field intensity in industrial environments and high voltage facilities. It is based on an MFS-3A three-axis magnetic field sensor, and it can measure magnetic flux density up to ±5 mT in all three axes, with accuracy better than ±0.5% and excellent temperature stability. The proposed teslameter was calibrated using a state-of-the-art reference instrument, Helmholtz coil and temperature chamber. The paper describes the development and the calibration of the proposed teslameter. The obtained results are presented as well.