Abstract: Resonator systems with controlled quality factors including a resonator having a plurality of ports and a first quality factor greater than the system quality factor, and an amplifier providing negative feedback among the ports to render the system quality factor independent of the resonator quality factor.

Abstract: Electrical impedance detector for measurement of physical quantities, in particular of temperature. The detector comprises electrodes (11,14), between which the electrical impedance (C;R) that represents the physical quantity to be measured is measured. Between these electrodes (11,14) there is an active material whose impedance properties are a function of the physical quantity to be measured. The active material of the detector is a very thin thread-like glass or glass-ceramic fibre (10), which has been manufactured by means of the glass-drawing technique. Further, a process for the manufacture of said detectors is described.

Abstract: A sensing electrode on a glass layer of an anodically-bonded capacitive sensor has an interfacial barrier film containing a nitride compound between the electrode and the glass layer. In one embodiment, the capacitive sensor is an inertial sensor having a sensing element hingedly mounted to a frame which is anodically bonded to the glass layer. The sensing electrode is then located on a surface of the glass layer facing the sensing element. The sensing element and the frame are preferably made of silicon and the interfacial film is preferably silicon nitride.

Abstract: A monolithic capacitive pressure transducer (12, 12') is made by separately forming under pressure a diaphragm (22, 22') and a base (24, 24') having a recess (14) in the top surface using ceramic powder coated with an organic binder. Metal layers are deposited on the two pieces and the pieces are then joined together to form a single unit. A spacer (36) may be inserted in the recess to ensure that a predetermined gap is maintained between the two parts during the joining operation. The parts are then heated to allow the binder organics, as well as the spacer organics if a spacer is employed, to be vaporized and/or decomposed and removed through the open pores of the diaphragm and base and then sintered to change the parts into a monolithic body and to convert the metallized layer into a conductive layer bonded to the ceramic.

Abstract: In order to obtain a stator of a variable capacitor, prepared is a ceramic laminate having a stator electrode provided in its interior and a plurality of burnaway films of carbon or resin, which can be burned away by firing, provided in positions corresponding to that of a concave portion in the form of layers. This ceramic laminate is fired to burn out the burnaway films thereby obtaining a sintered body provided with a plurality of cavities and a plurality of thin layers, and this sintered body is barrel-polished to crush the thin layers, thereby forming a concave portion. A rotor of a metal forming a rotor electrode is arranged on the stator obtained in the aforementioned manner. A cover of a metal is fixed to the stator through an engaging member engaging in the concave portion of the stator, to rotatably store the rotor while pressing the rotor against the stator by a spring action part.

Abstract: Apparatus for measuring the distance between a surface of a workpiece and a predetermined location of the type which measures the capacitance between the predetermined location and the workpiece surface and determines the distance corresponding to the measured capacitance. The apparatus includes a probe disposed at said predetermined location, the probe may be selectively excited to a known electric potential. A support assembly for supporting the workpiece is mounted on the apparatus for rotation relative to the probe. The support assembly is constructed to support the workpiece for rotation and to maintain the workpiece at a substantially constant electric potential. A grounding mechanism for grounding the support assembly includes a fixed grounding member and a liquid ground contact which engages the support assembly for maintaining electrical contact between the support assembly and the fixed grounding member as the support assembly rotates relative to the fixed grounding member.

Abstract: A Fingerprint sensing device and a recognition system having a row/column array of sense elements which are coupled to a drive circuit and a sense circuit by sets of row and column conductors, respectively. The sense elements are actively addressable by the drive circuit. Each sense element contains a sense electrode and a switching device (e.g., a TFT) for active addressing of that sense electrode. The sense electrodes of the sense elements are covered by insulating material adapted for receiving, directly thereon or on respective conductive pads overlying the sense electrodes, a finger. Capacitances resulting from individual finger surface portions in combination with sense electrodes are sensed by the sense circuit by applying a potential to the sense electrodes and measuring charging characteristics. In the fingerprint recognition system, an output from the sensing circuit is analyzed and characteristical data is compared with stored characteristical data for identification and verification purposes.

Abstract: A variable electronic component in the nature of a trimmer capacitor has greatly increased voltage rating and capacitance range, while eliminating possible failure modes. An annular opening formed in a stationary electrode is surrounded by plastic dielectric material so as to receive in interference fit a circular sleeve of an opposing impedance varying electrode. By filling the air gap with plastic dielectric material, no air contributes to the effective dielectric, while at the same time, preventing shorting as a result of loose metallic particles which might be present.

Abstract: A multibeam structure measures displacement of one or more response elements to detect multiple components of applied force. The flexible beams are each coupled to a response element which may be displaced by a force arising from linear acceleration, angular acceleration, fluid flow, electric/magnetic/gravitational fields, and other sources. The displacement of the response element is detected with a variety of sensing methods including capacitive and piezoresistive sensing.

Abstract: A capacitive acceleration sensor using a common PWB as one of the plates of the capacitive transducer and the wiring connections thereto. An acceleration input moves a capacitor plate to produce a measurable change in capacitance. An electronic signal conditioner accurately converts the capacitance output to a voltage signal to provide an acceleration sensor featuring accurate DC performance. The transducer and electronics are disposed on a PWB making up a complete sensor package. In a first embodiment, the capacitor comprises a fixed electrode on the PWB and a movable acceleration responsive electrode secured to a support by a conductive resilient member, the support coupled to an electrically conductive region on the PWB spaced from the fixed electrode by a guard ring to minimize stray charge between the capacitor electrodes.

Abstract: An electrode array for use in an apparatus for remotely monitoring the position of a rotatable member as the rotatable member is rotated by an axle about an axis. The array includes a substrate composed of a three-layer composite having first and second surfaces, a plurality of spaced-apart, excitable electrodes defining a center portion disposed on the first surface, an aperture in the substrate located in the center portion for receiving the axle, a center electrode in the center portion spaced apart from the axle circumscribing the aperture, a guard composed of a first conductive strip disposed in the center portion on the first surface spaced apart from and located between the spaced apart excitable electrodes and the center electrode. Each of the excitable electrodes have a concave free edge that delimits a part of the center portion.

Abstract: A measuring system in which flexible mats of individual cells are distributed in rows and columns of a matrix are individually pollable for converting mechanical pressures applied locally on surfaces of the mats, into electrical signals. Each cell constitutes a capacitor with capacitance that varies with the applied mechanical pressure. A source of voltage is connectable to each cell, and each cell has an upper surface and a lower surface. Pressure is applied to the upper surface, and a dielectric is positioned between the upper surface and the lower surface. The upper surface has a plurality of parallel strip-shaped areas with projections, whereas the lower surface has a plurality of parallel electrically conductive strip-shaped areas which extend at right angles to the first strip-shaped areas on one side of the dielectric to form a capacitor cell at each intersection. The intersections deforms resiliently under applied pressure to vary the capacitance under pressure.

Abstract: An inclinometer 20 has a sensing unit 40 for providing a varying capacitance signal depending on the orientation of the inclinometer 20. An oscillator circuit unit 82 includes the sensor unit 40 as a capacitive element for providing a signal having a period and a frequency depending on the capacitance of the sensor unit 40. A unit 92 is provided for determining the period of the signal. A look-up table unit 96 stores a predetermined relationship between the period of the signal and the angle of orientation of the inclinometer 20. A comparison unit 94 then compares the period of the signal to the period stored in the look-up table unit 96 and selects the corresponding angle which is the angle of orientation of the inclinometer 20. The angle is then displayed on the inclinometer display 25.

Abstract: A method of batch producing capacitive pressure sensors in which a sheet of semiconductive material is provided with an insulating layer 4 on one side thereof and a plurality of cavities 1 are formed in the semiconductive sheet by removing part of the insulating layer and part of the semiconductive sheet. Simultaneously with producing the cavities in the semiconductive sheet, at least one recess is provided, again by removing part of the insulating layer and part of the semiconductive sheet.

Abstract: A novel capacitive pressure-sensitive sensing technique and apparatus wherein an elastomeric conductive electrode carrying a two-dimensional array of projections is pressure-deformed against a fixed coextensive cooperative electrode to generate signals, such as tones and sounds in the application to musical instruments, or visual representations, corresponding to the dynamic pressures applied over the two-dimensional surface. A novel drum-like and other musical instruments embodying such novel capacitive sensing techniques and the like are described.

Abstract: A tuning capacitor arrangement for a microwave circuit including, on a substrate, first and second conductors to be capacitively joined. The tuning capacitor arrangement includes first and second capacitors each having connective tabs terminating on the substrate in the space between the first and second conductors. One or more connective pieces electrically connect one or more tabs to the conductors to determine the total capacitance between the first and second conductors.

Abstract: A keyboard-operated tone-producing apparatus having, in combination, keyboard means the keys of which are mounted for downward depression to effect tone production in the apparatus; electronic digital signal processor means; tone-generating means; pressure sensing means responsive to key depression to produce signals corresponding thereto for application to the signal processor means to produce corresponding digital signals applied to generate tones from the tone-generating means; means for causing the pressure sensing means to provide the same signal reference, upon key depression, irrespective of the point of pressure along the path of longitudinal sliding of the key; and means controlled in response to the last-named means and cooperative with the signal processor means as it controls the tone-generating means to produce one or all of variable range bending of the tone, center compensation for differing player techniques of key depression, and second striking of the key while depressed for second tone gene

Abstract: A platform weight scale comprising a capacitative load cell sensing means configured to be insensitive to off center loading of the horizontal platform regardless of load amount or location on the platform. The platform is supported by a plurality of springs selected for equal spring rates. The load cell is electrically connected into a FET (Field Effect Transistor), CMOS (Complementary Metal Oxide Semiconductor) or Bi-Polar semiconductor multivibrator circuit selected and designed to sense electric currents on the order of 10.sup.-13 amperes. In one preferred embodiment the load cell comprises a grounded hemispherical surface opposing a flat charged plate. In alternate embodiments the load cell comprises a differential capacitor or a parallel plate capacitor suspended in a manner that is insensitive to off center loading. An additional embodiment for the load cell comprises a spherically concave surface opposing the above grounded hemispherical surface.

Abstract: The microwave filter comprises resonators constituted by capacitor-coupled rejector circuits. The tuning and coupling capacitors are composed of parallel metal plates supported and separated by the dielectric of a substrate. The surface of at least one plate of each tuning and/or coupling capacitor is provided with windows which can be sealed-off by a metal deposit in order to permit adjustment of each capacitor to its optimum value.

Abstract: A sensor array includes a number of discrete elements each comprising a dielectric body and two electrodes. Dielectric body has an annular skirt and the electrodes define an annular gap in which an end portion of the skirt is located. Body is displaced relative to the electrodes upon application of pressure thereto, causing the skirt to further penetrate the gap and cause a detectable change in capacitance of the electrodes, related to the magnitude of the applied pressure. The dielectric bodies are supported by a common, resilient sheet which returns the bodies to a rest position when pressure is removed.

Abstract: A platform weight scale comprising a capacitative load cell sensing means configured to be insensitive to off center loading of the horizontal platform regardless of load amount or location on the platform. The platform is supported by a plurality of springs selected for equal spring rates. The load cell is electrically connected into a FET (Field Effect Transistor), CMOS (Complementary Metal Oxide Semiconductor) or Bi-Polar semiconductor multivibrator circuit selected and designed to sense electric currents on the order of 10.sup.-13 amperes. In one preferred embodiment the load cell comprises a grounded hemispherical surface opposing a flat charged plate. In alternate embodiments the load cell comprises a differential capacitor or a parallel plate capacitor suspended in a manner that is insensitive to off center loading. The differential capacitor load cell embodiment utilizes an alternating switch circuit as a part of the multivibrator circuit.

Abstract: The present invention provides an improved electrical double layer energy storage cell comprising a pair of electrodes, at least one of which is a carbon paste electrode, a porous ionically conductive separator and an ion insulated connector, the improvement wherein said carbon paste electrode comprises carbon exhibiting a pore volume of less than about 0.45 cc/gm and a median pore radius of less than about 150 Angstroms.

Abstract: A customizable impedance matching network for coupling a microwave transmission line to an FET. The network includes a plurality of conductive pads formed on the first surface of a dielectric substrate each pad providing in combination with the substrate and a conductor formed on an opposite surface of the substrate, a predetermined capacitance. Selective ones of such conductive pads are interconnected in parallel to form a capacitor having a capacitance related to the total surface area of such interconnected conductive pads, to provide the requisite capacitive reactance for the network. The network further includes a strip conductor formed on such first surface having a predetermined inductance per unit length and having a first end electrically connected to the network.

Abstract: A rotary electric component comprising a support structure made of synthetic resin, at least one first elongated electric terminal member made of electroconductive material and having one end positioned exteriorly of the support structure for the electric connection with an external circuit element, a rotor, and a second elongated electric terminal member made of electroconductive material and having one end positioned exteriorly of the support structure for the electric connection with an external circuit element. The second terminal member is supported by the support structure in the form as partially embedded in the support structure and has the other end formed into a tubular shaft for the support of the rotor for rotation thereabout. The shaft integral with the second terminal member is formed by the use of any known metal drawing technique and has a closed end at the tip thereof opposite to the second terminal member.

Abstract: An electronic circuit with a trimming capacitor with a first electrode in the form of a flexible sheet metal lug which is arranged in confronting relationship with a rigid counter electrode in the form of a plate capacitor. The flexible sheet metal lug and the plate capacitor are rigidly connected to an insulating support, for example a circuit board, and the capacitance of the trimming capacitor can be adjusted by bending the sheet metal lug.

Abstract: A servo motor system including a position sensor located within the motor air gap to virtually eliminate mechanical compliance in the servo loop. The transducer is of a capacitive type including interleaved capacitive plates and is designed to be substantially insensitive to the magnetic field of the motor.

Abstract: The present invention relates to a capacitive hygrometer comprising a capacitor (1) having a dielectric material (3), whose dielectric constant varies as a function of the quantity of water absorbed. It has on one of its conductive faces numerous fissures bringing the dielectric material into direct contact with the atmosphere whose degree of humidity is to be measured. However, the electrical continuity of the fissured conductive face is maintained. Application to the measurement of the degree of humidity of the air.

Abstract: A circular array of equally spaced, interleaved, reference elecrodes or pole pieces are arranged about the center of the array for producing an electric or magnetic field in which the resultant vector representing the maximum field strength rotates as a polyphase current or voltage source is successively applied to successive ones of the electrodes or pole pieces. In a preferred embodiment, each of the electrodes is uniquely and generally crescent shaped such that along any radius from the center of the array passing through a given electrode, the radial width of the electrode varies in proportion to the sine of A.multidot..theta. where A is an arbitrary constant and .theta. is the azimuthal angle of the radius as measured from the initial end of the electrode. The radial cross-section ratio may be achieved by varying the width alone, varying the elevation alone, or by a combination of the two.

Abstract: A variable capacitor, wherein at least one of its stator or rotor electrode is made of aluminum alloy or copper alloy and coated with a thin dielectric material layer containing fluorocarbon resin as its principal component by means of baking, is disclosed. The disclosed variable capacitor is particularly suited for a miniaturization of an appliance which adopts this variable capacitor. Careful qualification of the electrode materials, dielectric material, additional dielectric substance, and conditions for performing the baking and layer forming operation prevent the formation of the oxide film over the surface of the electrode material, and thus ensures a firm adherence of the layer to the substrate and a large maximum capacitance of the layer.

Abstract: A method for manufacturing variable capacitance pressure transducers and an intermediate article of manufacture produced in the practice of this method. In the method, a wafer of doped silicion or other semiconductor material has portions of the semiconductor material removed from spaced areas to form a plurality of recesses in the surface of the semiconductor material. The material is doped to enhance its electrical conductivity. A dielectric material has one of its surfaces coated with spaced areas of electrically conductive material. The semiconductor material is attached to the coated surface of the dielectric material such that the surface recesses in the semiconductor material are in alignment with the conductive areas on the dielectric material. This produces a plurality of electrical capacitors suitable for use as pressure transducers.

Abstract: A capacitor type displacement or load sensor includes a first electrode constituted by an electrically conductive coiled spring capable of expansion and contraction and a second electrode positioned to face the first electrode without making contact therewith. The second electrode is constituted by an electrically conductive coiled spring or a cylindrical electric conductor. The sensor is constructed such that capacitance between the first and second electrodes varies with a change of a gap between the first and second electrodes or an opposing area of the first and second electrodes caused by the relative displacement occurring therebetween.

Abstract: In capacitive systems comprising a dielectric sheet 11 having a first electrode 12 on one side, and on the other side in capacitive relation with the first electrode 12, second and third electrodes 13, 14 which are mutually spaced by a gap 15 especially for use in touch control switches, it is desired to achieve a favorable compromise between high capacitance modification as between touched and untouched condition of the first electrode 12, and the total amount of material used to form the electrodes.To this end, the third or outer electrode 14 is shaped to surround at least the major part of the periphery of the second or inner electrode 13, and the ratio of the area of the inner electrode 13 to the area of the outer electrode 14 is greater than 0.25 to 1.

Abstract: A precision linear tuning circuit having particular utility to applications employing superconductors in a supercooled environment. Two capacitors, one fixed and one variable, are connected in parallel by an arrangement of shared, concentric electrodes. The variable capacitor includes one electrode and a movable facing dielectric which are tapered such that displacement of the dielectric results in a linear variation in tuning frequency.

Abstract: A transducer for providing signals representative of the axial setting of an angularly movable component comprises a member having a first series of zones thereon, said zones having the same circumferential width and axial length and a sensing device having a sensing surface presented to the zones. As the area of the zones in turn presented to the surface of the device varies a fluctuating electrical signal is obtained which varies with the relative axial setting of the member and device. Calibration zones can be located between the zones respectively.

Abstract: A capacitive keyswitch is formed with a fixed horizontal plate that is imbedded in a horizontal printed circuit board below an overlaying dielectric layer and a moveable cantilever mounted plate that is hinged to the printed circuit board so as to project upwardly at an acute angle. When a plunger is actuated, a portion of it presses down on an overtravel mechanism that is formed from the moveable plate which causes the moveable plate to assume approximately a parallel position with respect to fixed horizontal plate, thereby changing the capacitance of the switch and actuating the switch. The overtravel mechanism consists of a tab cut out of a bent-up portion of the moveable plate so that the tab is bent along an intersection line formed by the intersection of the plane or moveable plate and the plane of the bent-up section.

Abstract: An electromagnetically compensating measuring apparatus, as in force measuring or weighing devices, wherein a compensation coil is wound upon a coil form movable in the air gap of a stationary permanent magnet system having a pole plate, a capacitive position sensor is connected to detect the position of the compensation coil, and an automatic volume control amplifier is series-connected to the position sensor so as to follow it, with the output of the amplifier connected to feed the compensation coil to tend to hold it in a predetermined zero position, and wherein the coil form and the pole plate each form an electrode of the position sensor.

Abstract: The present invention relates to a condenser for high power and with a gas shaped dielectric and preferably intended for tank circuits in high frequency generators and radio transmitters. The electrodes of the condenser consists of two metal tubes (1 and 2) with different diameters and located concentrically relative to each other. Those tubes are at both ends gas tight connected to each other so that a space is formed by the air gap between the tubes (1,2) which space can be filled with gas under pressure. The space inside the tube (2) with the smallest diameter is open and can be used for a transmitter tube to be located therein.

Abstract: An integrated semiconductor pressure transducer comprises a central conducting diaphragm located between two frusto-pyramidal recesses defined by contiguous semiconductor body members of conductivity type different from that of the diaphragm. A metal membrane with communicating apertures subtends one cavity and forms a relatively fixed plate of a capacitor, the other plate of which is formed by the diaphragm. A method of making the transducer in semiconductor process steps includes provisions for normal integrated circuit device fabrication whereby a transducer and utilization circuitry are fabricated in the same process into a single integrated semiconductor device.

Abstract: A variable capacitor for use in a keyboard comprises a stationary capacitor plate of thin, conductive, sheet material on an insulative substrate and having a substantially planar face. A movable member formed from a single piece of conductive sheet material includes a movable capacitor plate having a substantially planar, and continuous face in overlaying spaced apart relation to the stationary plate. The movable plate is struck from the body of a short length of a strip of sheet material to provide a pair of longitudinal side edges and an outer free edge transverse thereto, with a portion opposite the free outer edge projecting laterally outward and integral with a pair of supporting, spring-like, deflectable legs which extend downwardly toward the substrate to join an integral base strip mounted on the substrate.

Abstract: There is disclosed a capacitance probe for determining the level of high electrical resistance material in a vessel. The probe comprises at least two parallel, large surface area blades which are supported from a mounting plate and spaced apart to define a capacitance path. One blade is attached to an insulator body which is attached to the mounting plate while the other blade is directly attached to the mounting plate in electrical continuity therewith. The insulator body is a ceramic sleeve having a length sufficient to prevent shunting of the capacitance path. The probe is particularly intended for detection of level of fly ash and the like in a receiver vessel.

Abstract: A rotor for an adjustable low loss capacitor having a hollow cylindrical stator with an internally threaded bushing at one end, an axially adjoining insulative cylindrical body, a conductive end member and concentric radially spaced conductive tubes inside said insulative cylindrical body, comprises a rotatable cylindrical screw body having externally threaded portions for engaging internal threading of the bushing. The threaded portions are axially separated by an unthreaded intermediate portion of reduced diameter formed with three slots whose inner edges define an equilateral triangle axially of the screw body. The slots define three resilient springy webs each extending 120.degree. circumferentially of the screw body. Corners of each web are disposed in registration with the other two webs axially of the screw body. The intermediate portion is deformed slightly to misalign the two threaded portions of the screw body.

Abstract: A device for warning a person carrying or wearing it of the presence of dangerous microwave radiation is fully powered by the radiations being detected. A very low-wattage gas-discharge lamp is energized by a broadly or a sharply tuned receiver circuit including dipole antennas or one antenna and a "grounding" casing element. The casing may be largely and uniformly transparent or have different areas gradedly light-transmissive to indicate varying radiation intensities. The casing can be made in the shape of a pocket watch, fountain pen, bracelet or finger ring, etc.

Abstract: A variable capacitor includes a generally cylindrical insulating case made of synthetic resin, with a stator terminal, which has springiness at its contact portion, insert-molded therein. A dielectric body, having a stator electrode formed thereon, is nonrotatably housed in the insulating case along with a rotatable metal rotor having a rotor electrode, and a non-rotatable rotor terminal. The rotor terminal has springiness at its contact portion and is formed with an aperture through which the metallic rotor may be rotated for adjustment.

Abstract: A pressure-sensing capacitor and a method for trimming the capacitor is disclosed. The capacitor includes a pair of spaced flexible parallel quartz plates. A thin circular layer of conductive metal is formed on the opposing inner surfaces of the plates to define the electrodes of the capacitor. A glass frit sealing compound, forming a concentric ring about the conductive layers, is disposed between the plates to seal the evacuated space between the plates. The thickness of the ring is small enough so that the capacitance between the electrodes is higher by an unknown amount than the desired value of capacitance at every point in the range of variation of the value of pressure. The capacitor is trimmed by first measuring the capacitance value at zero pressure and also at a maximum pressure. The size and location of a path on one of the electrodes is computed from the measured capacitance values and the deflection characteristics of the plates.

Abstract: A weight scale includes a capacitive force load cell for linearly transducing force into electrical capacity. A C-shaped spring supports two capacitor plates adjacent the distal ends of the arms with the surfaces of the plates being normally parallel. Weight is transmitted from the platform of the scale to a pin which acts to separate the arms against the spring force. The plates are shaped, preferably triangularly, so that the change in capacitance as they separate is linear. The load cell is connected in circuit with an oscillator so that the change in capacitance is directly proportional to change in frequency as a measure of the weight of the load on the scale's platform.

Abstract: A rotary displacement capacitive transducer for indicating the angular position of a shaft comprises first and second cylindrical electrodes each electrode having inner and outer conducting members connected together by insulative adhesive and a part cylindrical screen mounted to the shaft is disposed between the electrodes and rotated with the shaft to vary the capacitance between the electrodes. The surfaces of the conducting members define the capacitance of the transducer.

Abstract: A capacitor comprising at least two electrodes separated from one another by an elastic dielectric formed of rubber and/or plastic for measuring forces acting upon one of the electrodes--the so-called measuring electrodes--by detecting the resultant change in capacitance. The dielectric in its unloaded state is pre-compressed and preferably possesses a number of hollow spaces.

Abstract: A method for manufacturing variable capacitance pressure transducers and an intermediate article of manufacture produced in the practice of this method. In the method, a wafer or doped silicon or other semiconductor material has portions of the semiconductor material removed from spaced areas to form a plurality of recesses in the surface of the semiconductor material. The material is doped to enhance its electrical conductivity. A dielectric material has one of its surfaces coated with spaces areas of electrically conductive material. The semiconductor material is attached to the coated surface of the dielectric material such that the surface recesses in the semiconductor material are in alignment with the conductive areas on the dielectric material. This produces a plurality of electrical capacitors suitable for use as pressure transducers.

Abstract: A trimmer capacitor comprises a metallic plate member which is generally U-shaped, and an elongate conductor member which is to be located inside the metallic plate. Both the metallic plate member and the conductor member can be fixed to a printed circuit board. By bending the conductor member to displace it inside the metallic plate member, the electrostatic capacitance formed between the metallic plate member and the conductor member can be varied.

Abstract: An apparatus for measuring the amount of relative displacement of mutually facing electrodes in such a direction as to cause a change in the distance therebetween, comprises:a power source generating an AC signal of a determined frequency;a phase-shifting means comprising a resistor and the mutually facing electrodes, the phase-shifting means being adapted to apply the AC signal to the mutually facing electrodes through the resistor and to generate an output signal of which the phase is shifted in response to the amount of relative displacement of the mutually facing electrodes; anda phase difference measuring means for measuring phase difference between the output signal of the phase-shifting means and the AC signal and generating a signal corresponding to the amount of relative displacement of the mutually facing electrodes.