The present invention relates to an electrode unit (10, 20) for an electric vacuum capacitor comprising a band-shaped capacitor plate (11, 21) with a height H, wherein the band-shaped capacitor plate (11, 21) is wound in a spiral with a maximum diameter D.sub.max and a constant distance between successive turns, wherein the band-shaped capacitor plate (11, 21) comprises a first longitudinal edge (11a, 21a) attached to a supporting part (12) and a second longitudinal edge (11b, 21b), the second longitudinal edge (11b, 21b) being free, wherein at the outer extremity of the spiral, the first longitudinal edge (11a, 21a) and the second longitudinal edge (11b, 21b) are connected by an inclined edge (11c, 21c) such that the first longitudinal edge (11a, 21a) is longer than the second longitudinal edge (11b, 21b), wherein the inclined edge (11c, 21c) forms with the longitudinal axis (B) of the band-shaped capacitor plate (11, 21) an angle α less than or equal to an angle α.sub.max=(45°.Math.π/180°). The invention relates also to a vacuum capacitor (30) comprising at least one electrode unit (10, 20) according to the present invention.

A variable capacitor includes an enclosure having first and second conductive collars separated by an intermediate electrically insulating element. A movable capacitor plate assembly is electrically coupled to the first conductive collar, and a fixed capacitor plate assembly is electrically coupled to the second conductive collar. An actuator extends into the enclosure for advancing and retracting the movable capacitor plate assembly relative to the fixed capacitor plate assembly. A hermetically sealed volume within the enclosure contains a dielectric fluid serving as a dielectric between a capacitor plate of the movable capacitor plate assembly and a capacitor plate of the fixed capacitor plate assembly. A flexible structure is provided to contain the dielectric fluid displaced when the movable capacitor plate assembly is advanced toward the fixed capacitor plate assembly.

A variable capacitor includes an enclosure having first and second conductive collars separated by an intermediate electrically insulating element. A movable capacitor plate assembly is electrically coupled to the first conductive collar, and a fixed capacitor plate assembly is electrically coupled to the second conductive collar. An actuator extends into the enclosure for advancing and retracting the movable capacitor plate assembly relative to the fixed capacitor plate assembly. A hermetically sealed volume within the enclosure maintains a vacuum or a liquid serving as a dielectric between a capacitor plate of the movable capacitor plate assembly and a capacitor plate of the fixed capacitor plate assembly. At least one capacitor plate comprises a coiled cylindrical plate having a having a greater height at a center portion of the capacitor plate coil and a lower height at an outer portion of the capacitor plate coil.

A variable capacitor includes an enclosure having first and second conductive collars separated by an intermediate electrically insulating element. A movable capacitor plate assembly is electrically coupled to the first conductive collar, and a fixed capacitor plate assembly is electrically coupled to the second conductive collar. An actuator extends into the enclosure for advancing and retracting the movable capacitor plate assembly relative to the fixed capacitor plate assembly. A hermetically sealed volume within the enclosure maintains a vacuum or a liquid serving as a dielectric between a capacitor plate of the movable capacitor plate assembly and a capacitor plate of the fixed capacitor plate assembly. At least one capacitor plate comprises a coiled cylindrical plate having a having a greater height at a center portion of the capacitor plate coil and a lower height at an outer portion of the capacitor plate coil.

Microelectromechanical sensor comprising a fixed part and a mobile part suspended from the fixed part such that the mobile part can move at least in an out-of-plane displacement direction, the fixed part comprising at least first electrodes extending parallel to the displacement direction of the mobile part, the mobile part comprising a seismic mass and at least second electrodes extending parallel to the out-of-plane displacement direction, the first electrodes and the second electrodes being located relative to each other so as to be interdigitated, in which the second electrodes are directly connected to the inertial mass and only part of the face of each mobile electrode is facing an electrode fixed at rest.

Microelectromechanical sensor comprising a fixed part and a mobile part suspended from the fixed part such that the mobile part can move at least in an out-of-plane displacement direction, the fixed part comprising at least first electrodes extending parallel to the displacement direction of the mobile part, the mobile part comprising a seismic mass and at least second electrodes extending parallel to the out-of-plane displacement direction, the first electrodes and the second electrodes being located relative to each other so as to be interdigitated, in which the second electrodes are directly connected to the inertial mass and only part of the face of each mobile electrode is facing an electrode fixed at rest.

A variable-capacitance capacitor having first and second electrodes mobile with respect to each other and third and fourth electrodes insulated from the first and second electrodes, capable of receiving a control signal to vary the relative position of the first and second electrodes in order to vary the capacitance between the first and second electrodes, the capacitor further including a system for controlling the position of the second electrode with respect to the first electrode, the system being arranged so that, for at least one relative position of the second electrode with respect to the first electrode, the position of the second electrode with respect to the first electrode is independent from the voltage between the first and second electrodes.

A variable-capacitance capacitor having first and second electrodes mobile with respect to each other and third and fourth electrodes insulated from the first and second electrodes, capable of receiving a control signal to vary the relative position of the first and second electrodes in order to vary the capacitance between the first and second electrodes, the capacitor further including a system for controlling the position of the second electrode with respect to the first electrode, the system being arranged so that, for at least one relative position of the second electrode with respect to the first electrode, the position of the second electrode with respect to the first electrode is independent from the voltage between the first and second electrodes.

The disclosure relates to a compensation capacitor for an antenna of a magnetic resonance scanner and a corresponding antenna with a compensation capacitor. The compensation capacitor has a first electrode and a second electrode arranged in parallel. An insulation material configured to resist high voltages and a dielectric with low dielectric losses are arranged between the first and the second electrode. The second electrode and/or the dielectric may be moved relative to the first electrode such that a surface area of a projection of the surface of the first electrode along the surface normal of the first electrode to the surface of the second electrode and/or the dielectric is variable.

An electronic pen includes: a tubular casing; a rod-shaped core body that projects outside of the casing through an opening of the casing, the opening being formed on one side in axial direction of the casing; a pen pressure detector disposed within a hollow portion of the casing, wherein the pen pressure detector, in operation detects a pen pressure applied to the core body; a core body insertion member disposed between the pen pressure detector and the opening of the casing within the hollow portion of the casing, the core body insertion member housing the core body movably in the axial direction of the casing and having a hollow space closed on a side of the pen pressure detector by a barrier; and a first sealing member that separates the hollow space of the core body insertion member from the hollow portion of the casing.