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 ? less than or equal to an angle ?.sub.max=(45?.Math.?/180?). The invention relates also to a vacuum capacitor (30) comprising at least one electrode unit (10, 20) according to the present invention.

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 ? less than or equal to an angle ?.sub.max=(45?.Math.?/180?). The invention relates also to a vacuum capacitor (30) comprising at least one electrode unit (10, 20) according to the present invention.

A method for assembling a force sensitive capacitor is provided. The method comprises: assembling an insulating member to a rear end of a rear-end moving part; inserting a front-end moving part and the rear-end moving part into a case from a front end and a rear end of the case, respectively, and assembling connecting portions of the front-end moving part and the rear-end moving part; assembling a compressible conductor to a front end of a conductor base; and inserting the conductor base into the case from the rear end of the case and assembling the conductor base to the case.

A method for assembling a force sensitive capacitor is provided. The method comprises: assembling an insulating member to a rear end of a rear-end moving part; inserting a front-end moving part and the rear-end moving part into a case from a front end and a rear end of the case, respectively, and assembling connecting portions of the front-end moving part and the rear-end moving part; assembling a compressible conductor to a front end of a conductor base; and inserting the conductor base into the case from the rear end of the case and assembling the conductor base to the case.

Systems, devices, and methods for micro-electro-mechanical system (MEMS) tunable capacitors can include a fixed actuation electrode attached to a substrate, a fixed capacitive electrode attached to the substrate, and a movable component positioned above the substrate and movable with respect to the fixed actuation electrode and the fixed capacitive electrode. The movable component can include a movable actuation electrode positioned above the fixed actuation electrode and a movable capacitive electrode positioned above the fixed capacitive electrode. At least a portion of the movable capacitive electrode can be spaced apart from the fixed capacitive electrode by a first gap, and the movable actuation electrode can be spaced apart from the fixed actuation electrode by a second gap that is larger than the first gap.

Provided is a long-life electret device preventing charge degradation of an electret element sealed in a closed space. The provided electret device includes a package member; a lid member; and an electret element. The lid member seals the package member to thereby form a closed space, the electret element is placed in the closed space, and a hydrogen getter is included in at least part of an inside of the closed space.

A plurality of core bodies are housed within a casing having an opening portion on one end side. A core body selecting mechanism is provided which includes a plurality of operating portions coupled to each of the plurality of core bodies, and makes at least a tip of one core body among the plurality of core bodies selectively project from the opening portion of the casing. A pen pressure detecting portion common to the plurality of core bodies is provided within the casing. When the operating portion is operated to make at least the tip of the one core body project from the opening portion, part of the operated operating portion engages with the pen pressure detecting portion common to the plurality of core bodies, and the pen pressure detecting portion detects a pen pressure applied to the tip projected from the opening portion.

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.

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.