Abstract: In a miniature, single-turn potentiometer, a fluid-tight seal is formed between the rotor and the housing by the interference fit between an annular ridge on the peripheral edge of the rotor and a conforming groove in the interior wall surface of the housing cavity in which the rotor is installed. In a preferred embodiment of the invention, there are two parallel ridges and grooves, and they are configured to form a "chevron" seal, in which the ridges have a substantially saw-tooth shape in axial cross-section, with the grooves having a complementary shape. The chevron seal provides a direct, rotor-to-housing seal that is fluid-tight, without the use of an O-ring, while also restraining the rotor from axial movement with respect to the housing.

Abstract: A miniature electronic device includes a housing attached to a substrate by a plurality of terminal leads, each of which has a first end embedded or molded into the housing near the top surface thereof, and a second end bent around a side wall of the housing to engage the bottom surface of the substrate. The bottom surface of the substrate has a plurality of metallized areas, each of which is electrically connected to a component on the upper surface of the substrate. The second end of each lead is soldered or welded to a metallized area. The connection of the leads to the metallized areas secures the housing to the substrate, with the leads also providing the structure for the electrical and mechanical connection of the substrate (and the components thereon) to a circuit board.

Abstract: In a digital transducer, the output of a piezoelectric transducer bridge is coupled to the input of a comparator whose output switches between two predetermined states. A series of digital values is generated in response to the state of the comparator output and is fed back to balance the bridge. Stored digital values control the span of the transducer.

Abstract: A modular encoder and switch assembly includes a first module containing the rotor and contact elements of an electrical encoder, and a second module that contains a switch. The two modules are axially aligned and joined together in tandem. The encoder and the switch are actuated by a common shaft that is rotatable to actuate the encoder and movable axially to actuate the switch.

Abstract: An improved resistive element comprises a film-type resistive layer applied to an insulative substrate and then fired. An array of discrete, spaced apart islands of predominantly conductive material is then applied to the resistive layer in a repetitive pattern having predetermined inter-island spacing. The islands have a conductivity that is substantially greater than the conductivity of the resistive layer. Preferably, the islands are of substantially uniform shape and size. In one preferred embodiment, the islands are formed of a conductive thick film ink that is screen-printed onto a cermet resistive layer through an appropriate mask, and then fired. In another preferred embodiment, the islands are formed of a conductive metal that is applied to the resistive layer by vapor deposition, sputtering, or ion implantation through a suitable mask.

Abstract: A contact for a rotary action variable resistor is formed of a length of wire coiled into a flattened, substantially annular spiral, with a wiper element provided by a radial protuberance on the spiral. A first embodiment has a protuberance along each of a first pair of diametrically-opposed radii. The spiral is eccentrically mounted on a substantially circular support plate, with one protuberance extending close to the peripheral edge thereof, and the other protuberance closer to the center of the plate. The spiral is attached to the plate along a second pair of diametrically-opposed radii approximately 90 degrees displaced from the first pair. The spiral is sloped so that the distance between the plate and the spiral gradually increases from the attachment radii to the protuberances. The protuberance near the edge of the plate is a resistive element wiper, and the protuberance nearer the center is the collector wiper.

Abstract: A linear variable differential transformer (LVDT), includes a hollow bobbin with first and second ends, a ferromagnetic core adapted for linear movement within the bobbin, a primary coil wound around the exterior of the bobbin, and first and second secondary coils wound around the primary coil. The first and second secondary coils are wound from starting points at the first and second bobbin ends, respectively. The seconardy coils are then wound continuously and simultaneously toward the opposite bobbin ends, so that the two secondary coils cross over each other at a cross-over point approximately halfway between the bobbin ends. The second secondary coil thus overlaps the first secondary coil between the cross-over point and the first bobbin end, and the first secondary coil overlaps the second secondary coil between the cross-over point and the second bobbin end. Each of the secondary coils has a sufficient continuous length to overlay substantially the entire length of the primary coil.

Abstract: An apparatus for winding two coils simultaneously on a bobbin, such as winding the two secondary coils of a linear variable differential transformer (LVDT), has a chuck or the like holding a bobbin. The chuck is rotated by a first motor. First and second wire guides move linearly in directions opposite to one another along the axis of rotation of the bobbin, and guide two strands of wire onto the rotating bobbin. The wire guides arrive simultaneously at the longitudinal center of the bobbin where the two strands of wire cross one another. The two wire guides are driven by two lead screws which rotate at identical speeds but in opposite directions to one another. The lead screws are driven by a second motor. The speeds of rotation of both motors are controlled by a computer, whereby the pitch pattern of the windings is determined by a computer program.

Abstract: A pressure transducer of the type employing a pressure-responsive diaphragm (11) with silicon piezoresistive strain gauges epitaxially deposited thereon is provided with integral digital thermal compensation of span shift and zero shift. The strain gauges are connected in a bridge circuit (30), and a differential voltage across the bridge circuit is amplified by an instrumentation amplifier (46). A temperature sensitive resistor (36) is deposited on the pressure-responsive diaphragm. This resistor is connected in a bridge circuit (35) the output of which is connected to an analog-to-digital (A/D) converter (54) which generates a digital number corresponding to the measured temperature of the piezoresistive strain gauges. This digital number is used to address pre-programmed correction data stored in a programmable read only memory (PROM) (53). The numerical correction data from the PROM is converted by a digital-to-analog (D/A) converter (55) to an analog correction signal.

Abstract: An improved resistive element comprises a film-type resistive layer applied to an insulative substrate and then fired. An array of discrete, spaced apart islands of predominantly conductive material is then applied to the resistive layer in a repetitive pattern having predetermined inter-island spacing. The islands have a conductivity that is substantially greater than the conductivity of the resistive layer. Preferably, the islands are of substantially uniform shape and size. In one preferred embodiment, the islands are formed of a conductive thick film ink that is screen-printed onto a cermet resistive layer through an appropriate mask, and then fired. In another preferred embodiment, the islands are formed of a conductive metal that is applied to the resistive layer by vapor deposition, sputtering, or ion implantation through a suitable mask.

Abstract: A contact assembly has a contact comprising two wire loops in an overlapping relationship, with a leg of each loop being interposed between the legs of the other loop. The prong forms the shank of a terminal pin, joined at an angle to a segment of the metal strip, which forms a tab portion of the pin. The contact is joined at one end of each loop leg to the tab portion, with the closed ends of the loops extending away from the tab/shank juncture. The closed ends of the loops are thus resiliently cantilevered from the pins to form a resilient, multi-wire contact.

Abstract: A retention mechanism for retaining an electrical element securely within a housing is specifically adapted for use with a loop-shaped (e.g., substantially annular) electrical element, having two ends separated by a small gap. The mechanism comprises a gap-registrable member in the housing cavity containing the electrical element, whereby the gap-registrable member registers with, and fits into the gap of the electrical element when the latter is seated on a seating surface in the cavity. The gap-registrable member is dimensioned to spread the gap, thereby radially expanding the electrical element to bring it into a locking frictional engagement against the walls of the cavity. The gap-registrable element advantageously serves also as a stop for a rotational contact, or wiper, included with the electronic device. The side wall of the cavity is advantageously provided with a radially-inwardly extending lip that is engageable with the electrical element to restrain it from lifting off of the seating surface.

Abstract: A method for manufacturing a contact assembly for an electronic component commences with providing (1) a length of wire formed into a continuous series of loops each having a pair of legs joined at a closed end, the series of loops comprising first and second pluralities of loops extending laterally in opposite directions from a longitudinal axis, each loop in one plurality axially located between the legs of a loop in the other plurality; and (2) a strip of metal having a plurality of prongs extending laterally from one side and spaced apart by the same distance as are the loops in the first plurality. The prongs are bent to form a slightly acute angle with the strip. The length of wire is attached to the strip so that each of the first plurality of loops extends into the space previously occupied by a prong before it was bent, the second plurality of loops extending outwardly from the opposite side of the strip.

Abstract: In an electronic device, of the type having an electronic component carried on a substrate, a housing to enclose the component, and terminal leads attached to the substrate, the housing is attached to the substrate by means of crimped tabs formed on extensions of the terminal leads. The extensions are directly generally perpendicularly to the substrate, and they terminate in inwardly-bent tabs which engage the housing in slots provided in the top surface of the housing. The tabs are crimped downwardly into the slots to lock the housing onto the substrate. An O-ring may optionally be retained in the housing, whereby the crimping of the tabs compresses the O-ring against the substrate to provide a substantially hermetic seal.

Abstract: A diaphragm-type pressure sensor employs a monocrystalline wafer as a pressure-responsive diaphragm. The wafer has a central active area surrounded by a first bonding area on one side and a second bonding area on the other side. The first bonding area is attached by a first layer of bonding material to a base, and the second bonding area is attached by a second layer of bonding material to a cap. The inside diameter of the first bonding layer is greater than the inside diameter of the second bonding layer by an amount of at least approximately six times the thickness of the diaphragm. This disparity between the respective inside diameters of the two bonding layers results in the relief of radially-directed tensile loading on the first bonding layer when a pressure to be measured is applied to the first side of the diaphragm. Consequently, the probability of a fracture occurring in this bonding layer is minimized.

Abstract: Silicon capacitive pressure sensors are produced by a batch-process method, comprising the steps of: (1) providing first and second wafers of conductive silicon; (2) oxidizing a surface of each wafer with a layer of silicon dioxide; (3) removing a predefined area of the silicon dioxide layer from a first one of the wafers, leaving an exposed surface of unoxidized silicon in the predefined area; (4) superimposing the second wafer onto the first wafer so that the silicon dioxide layer of the second wafer is in contact with the silicon dioxide layer of the first wafer; (5) fusing the two wafers together at their contacting silicon dioxide layers; (6) metallizing selected areas of the outer surfaces of the two wafers to form electrical contacts; and (7) cutting the wafers into individual pressure sensors.

Abstract: A socket for an integrated circuit device, particularly of the "Small Outline" type, includes a receptacle having a base and a pair of opposing side walls. A row of spaced-apart, generally vertical guide members extending inwardly from the interior surface of each side wall defines a row of generally vertical slots adjacent the interior surface of each side wall. Near the bottom of each slot is an electrical contact, comprising a pair of elongate, overlapping wire loops, each having a leg interposed between the legs of the other loop. The contact has one end conductively connected to an interior portion of a conductive pin which extends through the base of the receptacle. The other end of the contact is a free end that exhibits a resilient flexibility. A cover is provided with two opposed rows of downwardly-extending fingers, each of which is registrable with, and receivable in, one of the slots.

Abstract: A pressure transducing device in the form of a beam includes a monolithic chip of silicon or similar material which is mechanically supported at and near its two opposed ends and unsupported in a flexible region between the two ends. The flexible, unsupported region is one of maximized sensitivity to stresses produced by deflection or flexing of the beam due to, e.g., a differential pressure applied across it. An integral, pressure-responsive diaphragm is formed in the supported area of the chip near one of its mechanically-supported ends. This area of the chip is relatively insensitive to stresses produced by beam flexing or deflection; rather, it responds to stresses produced by a pressure (e.g., a static pressure) applied directly to its surface. A first set of strain gauges is provided in the flexible chip region, and a second set on the surface of the integral diaphragm.

Abstract: An integrated circuit semiconductor chip or the like is packaged on a leadless chip carrier. The chip carrier comprises a substrate with an integral coplanar extension frangibly connected to one or more sides. Each such extension has a metallized conductive area forming a shorting bar, interconnecting at least some of the metallized conductive traces formed on the substrate. The extensions with the shorting bars remain attached to the substrate while the chip is being installed to prevent damage to the chip from electrostatic discharges. After chip installation is completed, the extensions are separated from the substrate, thereby removing the interconnections between the traces. In a preferred embodiment, a scoring line along the peripheral edge of the substrate provides the frangible connection to the extension, and the extension is provided with holes along the scoring line to allow side metallization of the substrate.

Abstract: In an apparatus for encapsulating objects in molded plastic packages, an improved removable cavity plate assembly comprises upper and lower cavity plates which fit together in an interlocking manner to define molding cavities having integral surfaces formed within a single cavity plate on all sides of the cavity but one. The fourth side of each cavity is defined by a surface formed by the interlocking juncture between the two cavity plates. Plastic packages molded in the cavities thus are formed without a seam or parting line along the sides formed on the integral molding surfaces, the seam or parting line being formed only on the surface defined by the juncture of the two cavity plates.