Abstract: A method for measuring an alternating electric field is disclosed. The method includes realizing a first diffraction grating in a first location, in a core of a silica-based optical fiber, and measuring a peak reflection wavelength of the first diffraction grating. The method also includes positioning the optical fiber along a direction having a non-zero component of an electrical field generated by an alternating voltage to be measured, and coupling a substantially monochromatic light to said optical fiber surrounded by the electric field. The method further includes measuring a parameter dependent on a shift of the peak reflection wavelength due to intrinsic mechanical deformation or refractive index change of the material in which the optical fiber and the diffracting grating are realized due to the alternating electric field, and calculating a value of the electric field causing such a measured deformation or refractive index change.

Abstract: A method for measuring an alternating electric field is disclosed. The method includes realizing a first diffraction grating in a first location, in a core of a silica-based optical fiber, and measuring a peak reflection wavelength of the first diffraction grating. The method also includes positioning the optical fiber along a direction having a non-zero component of an electrical field generated by an alternating voltage to be measured, and coupling a substantially monochromatic light to said optical fiber surrounded by the electric field. The method further includes measuring a parameter dependent on a shift of the peak reflection wavelength due to intrinsic mechanical deformation or refractive index change of the material in which the optical fiber and the diffracting grating are realized due to the alternating electric field, and calculating a value of the electric field causing such a measured deformation or refractive index change.

Abstract: In an electromagnetic actuator, which comprises a stator, a translator movable along a guiding element, and an excitation coil for generating an electromagnetic force which moves the translator, the coil is supplied with an electric current obtained according to the sum of a first electric signal, the time pattern of which defines a desired motion of the translator, with a second electric signal, which is generated only at each of given level variations of the first electric signal by modulating an oscillating function with a decreasing, time limited function, so that the second signal has an amplitude envelope having a certain maximum width such that the electromagnetic force is subjected to a higher increase of the static friction force between the translator and the guiding element.

Abstract: An electromagnetic actuator for a proportional solenoid valve, which actuator has a fixed ferromagnetic core having a longitudinal axis, a plunger movable with respect to the fixed core along the axis between two stroke end positions, a spring for moving the plunger to the first stroke end position, an energizing winding to generate an electromagnetic induction field which produces a force against the bias of the spring and such that it moves the plunger to a equilibrium position between the stroke end positions, and wherein a surface portion of the plunger is increasingly facing a surface portion of the fixed core as the plunger approaches the second stroke end position, so that the electromagnetic induction field has an increasing number of force lines which close in the air gap between the fixed core and the plunger by crossing the first surface portion of the fixed core orthogonally to said axis.