Abstract: A cavity, such as an oven cavity, is heated by at least one monolithic integrated heat source, each fabricated by depositing a layer of resistive material on a substrate of non-conducting, or insulating, material. A pair of spaced-apart conductive elements contact opposite ends of the resistance sheet to enable a flow of current through the sheet thereby producing substantially uniform heating over the entire area covered by the resistive sheet.

Abstract: Sensor and method of fabricating a sensor for detecting relative humidity with a substantially linear response from 0% to 100% and also detecting temperature. The sensor utilizes a unique essentially pure Al.sub.2 0.sub.3 layer which has a disordered crystalline structure and a density gradient which varies from a low density at its lower surface to a higher density at its upper surface which together produce the desired linear response to relative humidity. The method of producing the unique essentially pure Al.sub.2 O.sub.3 layer includes anodizing with an ac current in a solution of approximately 6.4 normal acid at a starting temperature of 21.degree. C. and allowing the temperature of the anodizing solution to rise with the process to vary the density of the Al.sub.2 O.sub.3 layer. The Al.sub.2 O.sub.3 layer is neutralized in a base solution, washed in boiling water and alcohol to neutralize the Al.sub.2 O.sub.3 layer and remove impurities.

Abstract: A hair curler comprising an elongated substantially hollow hair bobbin includes a PTC heating element having a temperature self-controlling function housed within the hair bobbin. A pair of opposed cup-shaped generally cylindrical members are housed within the bobbin with each cylindrical member including a bottom and a side wall. The heating element is held between the opposed bottoms of the cup-shaped members. Each of the bottoms of the cup-shaped members defines an electrode plate arranged in contact with a respective side of the heating element for transmitting electricity to the heating element and conducting heat from the heating element to the side wall of the respective member. The side wall of each member defines conductors for transmitting the heat to the ends of the hair bobbin. A power supplying pin includes first and second power supplying terminals which are connected to a respective one of the electrode plates.

Abstract: A packaging arrangement for an electrical heater unit adapted for adhesive attachment to a surface, for example, to a window of a motor vehicle. The heater unit includes a plurality of heater strips which have an adhesive coating on one face thereof whereby the strips may be secured to the window. The strips are supported in a desired pattern for application to the window by being adhesively mounted on one surface of a backing sheet. The adhesive coated surfaces of the strips are remote from the backing sheet and a removable cover sheet overlies the heater strips. A clearance is provided between the cover sheet and the adhesive coating on the heater strips so that the cover sheet is not contacted by the adhesive coating on the heater strips.

Abstract: A heated hair straightener has a handle connecting to an electric source and a pair of scissor-like clamp housings pivoted on the handle and having facing coverplate surfaces for clamping and straightening the hair. This combination has an improvement in the heater sub-assembly fitting in one of the housings and formed as a sandwich arrangement including an aluminum coverplate, a copper elongated heater plate forming a first electrode connected to one side of the line and electrically insulated from the coverplate by a thin dielectric film. Plural PTC heater pellets are aligned on the heater plate and held by an insulating locator panel having cut-outs fixing the pellets on the heater plate. A second electrode, formed as a corrugated stainless steel spring plate covers and abuts the PTC pellets and is connected to the other side of the line. Next is a phenolic or ceramic insulator member with a recess for the corrugated spring plate to fit and abut therein.

Abstract: A collapsible cordless electric hair curling appliance includes a hollow handle adapted for grasping by a user. A heating wand is extensibly slidably retained in the hollow portion of the handle. An improved positive temperature coefficient heating element assembly is positioned inside the wand. An electric plug assembly is also slidably mounted in the hollow portion of the handle. The plug is mounted so as to extend from the handle for connection with a conventional electric socket only when the wand is substantially fully inserted into the hollow handle. The novel plug assembly eliminates the need for a conventional electric cord and is also rotatably mounted in the handle to provide added convenience for plugging the appliance into a conventional electric socket. For storage, both the wand and plug assembly may be enclosed within the handle.

Abstract: A printed circuit substrate with a resistance coat comprises an insulating support having provided at least on the one side thereof a highly conductive material layer interposed with a resistance coat. The resistance coat comprises tin-nickel alloy.

Abstract: A heating device for heating a glass surface, such as the rear window of a car, includes a pair of elongated electrically non-conductive carrier strips having an adhesive layer on both sides thereof and secured in spaced-apart relationship to the glass surface by one of their adhesive layers to laterally delimit the surface area of the glass encompassed by the heating device. A plurality of spaced, thin electrically conductive foil strips, each cut in predetermined lengths from a continuous strip, and each of which has an adhesive layer on one side, extend between the carrier strips. The ends of the foil strips overlie the carrier strips and are secured to the carrier strips and the glass surface by the adhesive layer thereof. A strip-shaped electrical terminal conductor overlies each carrier strip in electrically conductive engagement with the foil strip ends and is fastened to the carrier strip by the other adhesive layer on the carrier strip exposed between the foil strip ends.

Abstract: A self-regulating heating element comprising a tubular body closed at each end and containing two longitudinal electrically and thermally conductive flat strips arranged parallel to and spaced from each other. Each flat strip is provided along at least one longitudinal edge thereof with an abutting longitudinal resilient heat-conductive strip conforming with the adjacent surface of the inner wall of the tubular body so as to be in resilient heat-exchange contact with such inner surface for conducting heat from the flat strip to the tubular body. At least one PTC resistor is positioned between and in electrical and heat-exchange contact with the parallel flat strips, electrical terminals extending through the tubular body into contact with the flat strips. Such heating elements find particular use as immersion heaters for liquids and as the heat source in hair-curling devices.

Abstract: A positive temperature coefficient (PTC) resistance heater assembly is used in combination with an angle of attack vane to provide automatic means for maintaining the temperature of the vane at a level which will de-ice the vane. The heater assembly is embedded in a recess in the vane and is made up of a plurality of individual PTC resistors connected electrically and mechanically in parallel by flexible electrically conductive perforated strips which permit the individual resistors to move relative to each the other under thermal stress and which also permit the encapsulation of the resistors in a suitable thermally conductive, electrically oinsulative material that is sufficiently resilient to permit the individual resistors to expand and contract relative to the vane during use.

Abstract: An electrical resistor comprising a base having a resistance element supported thereon. A pair of terminals for connecting the element into an electrical circuit are bonded to the resistance element. The bond comprises a conductive thermoplastic bondable material applied to the resistance element before the terminals are secured thereto. Heat applied to the terminals causes the bondable material to flow and bond the terminals to the resistance element. In one embodiment, a rotatable knob, a contactor and a collector are assembled to the resistor to produce a variable resistance control. The knob is provided with a first skirt extending toward the base and in slideable engagement therewith. The first skirt supports the knob in spaced relationship with the base and a second skirt extends toward the resistance element carried by the base. The distal end of the second skirt is disposed proximate to the resistance element and encloses and protects the resistance element against external contaminants.

Abstract: An electronic printed circuit is produced by firstly forming an electric resistance layer on an insulating substrate at positions where resistors and conductive portions of the printed circuit are expected to be provided, and then applying a layer of electrically conductive substance over the electric resistance layer thus formed, at positions where the terminals and the conductive portions of the printed circuit are to be provided.

Abstract: A termination material for a vitreous enamel electrical resistor includes a mixture of a glass frit and particles of either molybdenum, tungsten, tantalum or titanium. The termination material is applied to a substrate and fired to melt the glass frit, and then cooled to form a layer of the glass with the metal particles embedded therein. The termination material may be applied to the substrate either before or after the resistance material is applied to the substrate and is particularly useful with vitreous enamel resistance materials which include either a mixture of tantalum nitride and tantalum, a mixture of tungsten carbide and tungsten, or an alloy of copper and nickel.

Abstract: Disclosed is a resistor comprising a nonconductive substrate on which is disposed a rectangularly-shaped coating of resistive material having a negative TCR. Oppositely disposed along the longer sides of the coating is a pair of elongated, parallel strips of resistive material having a positive TCR. Electrical connection is made to the opposed ends of the coating and to an end of each strip. The strips and electrical connections are so disposed that at low temperatures, current flow is predominantly across a relatively wide, short path in the coating between the strips, and at higher temperatures, current flow is predominantly along a longer, narrower path in the coating which is parallel to the strips.

Abstract: A drawer type electrode of a thermistor for sensing high temperatures, wherein a shaft and a sheath are connected to a thermistor, is constructed such that the shaft and the sheath are brought into contact with the positive and negative electrode surfaces of the thermistor through precious metal chips so that electrical connection between the precious metals, the shaft and the sheath will not be impaired in any way even if oxidation penetrates into the interior from the shaft and the sheath surface due to high temperature.

Abstract: A termination material for a vitreous enamel electrical resistor which includes a mixture of a glass frit and particles of nickel and iron. The termination material is applied to a substrate and fired to melt the glass frit, and then cooled to form a layer of the glass with particles of an alloy of nickel and iron embedded therein. The termination material may be applied to the substrate either before or after the resistance material is applied to the substrate.

Abstract: An electrical resistor and method of making same including a substrate of an electrical insulating material having on a surface thereof a film of a resistance material and a termination film of a conductive material at each end of the resistance film. The resistance film is preferably a layer of a glass having embedded therein conductive particles such as tantalum nitride and tantalum or tungsten carbide and tungsten. The termination film contains either molybdenum, tungsten or a mixture thereof.

Abstract: The invention relates to adhesive compositions comprising vinyl containing organopolysiloxanes, organopolysiloxanes having Si-bonded hydrogen atoms and catalysts which promote the addition of the Si-bonded hydrogen atoms to the vinyl groups.These adhesives may be combined with other electrically conductive materials and used in connecting flexible heating resistors to electrodes.

Abstract: A method of making electrical resistors, in particular N.T.C. resistors for high temperature applications. The body of resistance material is provided with electrodes; and the ends of the leads are clamped against the electrodes in a case consisting of ceramic material which shrinks during sintering.

Abstract: A cermet resistor employs film terminations of sub-micron thickness. The terminations contain particles of SiO.sub.2 or MnO.sub.2 that may be conveniently made by mixing such particles in a metal resinate paste, screening the paste on a glazed or unglazed substrate and firing. A glass containing resistor paste is screened in overlapping relationship with the fired terminations and is itself fired. The particle additives ameliorate cracking of the terminations at resistor firing and enhance the termination to substrate bond.

Abstract: Measuring cell for determining oxygen concentrations in a gas mixture, which cell comprises two elements made of a semiconductive oxidic material which is doped so as to have n-type and p-type conductivity respectively and which are separated by a metal layer, the electric resistance of the said semiconductive oxide depending upon the oxygen pressure. The cell is used for carburation control in an internal combustion engine.

Abstract: An electrical heater device includes a disc-like ceramic resistor element of a material of positive temperature coefficient of resistivity having contact surfaces formed on a broad opposite sides of the element. A pair of device terminals engage respective contact surfaces of the resistor element for directing electrical current through the element. At least one of the terminals has a plurality of protuberances resiliently engaged with a limited area of one contact surface of the resistor element to provide good electrical connection to the element in a convenient manner. In addition, an inert silicone material having a metallic particulate dispersed therein is disposed between the terminal and the remaining area of the contact surface of the resistor element to maximize heat transfer from the element to the terminal so that heat generated by the resistor element is efficiently emitted from the heater device.

Abstract: A heater on metal composite unit. A strip of metal has a stripe of an electrically insulative and thermally conductive synthetic resin material bonded to one surface along the length thereof. At least one stripe of an electrically conductive material, having a width less than the width of the insulative stripe, is bonded to the surface of the insulative stripe along the length thereof. A strip of electrical resistance material at least partially overlies the stripes of both the conductive and insulative materials thereby providing a path of electrical resistance material from the conductive stripe transversely across a portion of the width of the insulative stripe whereby when electrical current flows through the electrical resistance material it will supply heat to the metal strip. Apparatus and a process for fabricating these composite units are also disclosed.