Abstract: A method of making a positive temperature coefficient of resistance (PTCR) device, and the PTCR device itself, where there is provided a ferroelectric semiconductor having a Curie point and a bulk resistance. A layer of electrically conducting material is provided upon the ferroelectric semiconductor. The layer is heated at a process temperature greater than the Curie point of the ferroelectric semiconductor for a period of time, and cooled to ambient temperature. The process temperature and time period are selected to be sufficent to provide an ambient layer resistance greater than the bulk resistance of the ferroelectric semiconductor. The layer may be heated in an oxidizing atmosphere or in a reducing atmosphere, which also affects the layer resistance. The ferroelectric semiconductor may be in the form of an oxide ceramic or liquid crystals, and may include barium titanate. The layer may be selected from the group consisting of metal, metal alloys, metal oxides, polymers, and composites thereof.

Abstract: Apparatus and method for determining the concentration of NOx in a gas mixture. The gas mixture is supplied to two electrodes at which different NOx decomposition conditions are present. The electrodes may be of different materials or sizes or may be positioned in different gas enclosure environments. The NOx decomposes at different rates at the two electrodes and an emf is thus produced between the electrodes. The concentration of NOx in the gas mixture is determined from the measured emf.

Abstract: A system of dielectric ceramic compositions suitable for various microwave applications. The system comprises a plurality of stoichiometrically-related compositions, each composition having its own particular set of dielectric properties and consisting essentially of a sintered mixture represented by the general formula:BaTi.sub.4-w M.sub.w O.sub.9 --xZn.sub.2 TiO.sub.4 --yBaO--zTa.sub.2 O.sub.5wherein M is at least one type of metal and 0.0.ltoreq.w.ltoreq.about 0.05 and wherein x, y, and z are molar fractions of respective components with values within the following respective ranges: 0.0.ltoreq.x.ltoreq.about 0.45; about 0.01.ltoreq.y.ltoreq.about 0.20; and 0.0.ltoreq.z.ltoreq.about 0.10.

Abstract: A method of making a positive temperature coefficient of resistance (PTCR) device,and the PTCR device itself, where there is provided a ferroelectric semiconductor having a Curie point and a bulk resistance. A layer of electrically conducting material is provided upon the ferroelectric semiconductor. The layer is heated at a process temperature greater than the Curie point of the ferroelectric semiconductor for a period of time. End cooled to ambient temperature. The process temperature and time period are selected to be sufficient to provide an ambient layer resistance greater than the bulk resistance of the ferroelectric semiconductor. The layer may be heated in an oxidizing atmosphere or in a reducing atmosphere which also affects the layer resistance. The ferroelectric semiconductor may be in the form of an oxide ceramic or liquid crystals, and may include barium titanate. The layer may be selected from the group consisting of metal, metal alloys, metal oxides, polymers, and composites thereof.

Abstract: Apparatus and method for determining the identity and concentration of a component in a test atmosphere having a known concentration of oxygen. At least one solid electrolyte oxygen sensor is used, with each sensor having a solid electrolyte wall in contact with, and interposed between, a first electrode and a second electrode. The first electrode is in communication with the test atmosphere. A first negative voltage is applied across the first and second electrodes of a sensor, causing electrochemical oxygen pumping and a first electric current to flow through the corresponding solid electrolyte wall. The first negative voltage is selected to cause the first electric current magnitude to be on a first current plateau. The magnitude of the first electric current is measured.A second negative voltage is applied across the first and second electrodes of a sensor, causing electrochemical oxygen pumping and a second electrical current to flow through the corresponding solid electrolyte wall.

Abstract: Apparatus and method for determining the concentration of NOx in a gas mixture. The gas mixture is supplied to two electrodes at which different NOx decomposition conditions are present. The electrodes may be of different materials or sizes or may be positioned in different gas enclosure environments. The NOx decomposes at different rates at the two electrodes and an emf is thus produced between the electrodes. The concentration of NOx in the gas mixture is determined from the measured emf.

Abstract: A fuel cell which converts chemical energy from a fuel/oxidant gas mixture to electricity for power usage or gas-sensing applications is disclosed. The fuel cell has a solid electrolyte wall with electrodes on each side. Each side of the wall is surrounded by a partition which forms a first and second chamber whereon the fuel/oxidant gas mixture is allowed to diffuse. Means are provided to initiate a voltage drop between the electrodes which initiates the chemical reaction. Electricity is collected from the electrodes. In an alternate design the fuel cell has a first and second electrolyte wall with electrodes on each side of the walls. A partition wall separates the first and second walls thereby forming a first chamber with the first wall and the partition wall and a second chamber with the partition wall and the second wall. Gas-flow limiting means exist between the fuel/oxidant gas mixture and the first chamber and the first chamber and the second chamber.

Abstract: Apparatus and method for determining the identity and concentration of one or more components in a test atmosphere having a known concentration of oxygen. A solid electrolyte oxygen sensor is used, having a first solid electrolyte wall in contact with, and interposed between, a first electrode and a second electrode and a second solid electrolyte wall in contact with, and interposed between a third electrode and a fourth electrode. The second and fourth electrodes are in communication with the test atmosphere. A partition wall separates the first and third electrodes forming a first chamber bounded by the first wall and the partition wall and a second chamber bounded by the partition wall and the second wall. Diffusion limiting means inhibit gas-flow of the gas from the test atmosphere to the first chamber and from the first chamber to the second chamber.

Abstract: A method for identifying and determining the concentration of nitrous oxide in a gas containing nitrous oxide, oxygen and nitrogen is disclosed. A negative voltage is applied across a set of electrodes separated by an electrolyte wall. The voltage is of such a magnitude to produce an electric current which is on a plateau. The current is measured initially using air or oxygen as a test gas. After this reading is taken the gas containing nitrous oxide in oxygen and air is measured for its current and the concentration of nitrous oxide is determined using the two measured currents. The negative voltage can be applied at two different magnitudes to have two currents measured. Nitrous oxide containing mixtures would yield equivalent current readings.

Abstract: Apparatus for measuring the concentration of oxygen in exhaust gases. A gas sensor element of yttria-stabilized zirconia (Y.sub.2 O.sub.3 -ZrO.sub.2) has at one end a gas pump of two chambers separated by intervening Y.sub.2 O.sub.3 -ZrO.sub.2 with an orifice extending between each chamber and the exterior of the gas sensor element. Two platinum electrodes of a first set face one chamber and two platinum electrodes of a second set face the other chamber. The gas sensor element is mounted in an insulating mounting collar in close contact with two ceramic heaters of resistance heating elements on silicon nitride substrates. The mounting collar is clamped between a shield member encircling the gas pump of the sensor element and a housing member by threaded clamping nuts. The shield member has one or more apertures therein to admit exhaust gases to be analyzed to the gas pump of the sensor element.

Abstract: A layer of chemically compatible conductive material is applied to ferroelectric semiconductor material having a permanent polarization below its Curie temperature. The materials are heated to a temperature above the Curie temperature of the ferroelectric semiconductor material and allowed to cool. The result is a low resistance contact. The ferroelectric semiconductive material may be a layer on a non ferroelectric semiconductor material with a matching work function or matching dopant levels.

Abstract: Apparatus for measuring the concentration of oxygen in exhaust gases. A gas sensor element of yttria-stabilized zirconia (Y.sub.2 O.sub.3 -ZrO.sub.2) has at one end a gas pump of two chambers separated by intervening Y.sub.2 O.sub.3 -ZrO.sub.2 with an orifice extending between each chamber and the exterior of the gas sensor element. Two platinum electrodes of a first set face one chamber and two platinum electrodes of a second set face the other chamber. The gas sensor element is mounted in an insulating mounting collar in close contact with two ceramic heaters of resistance heating elements on silicon nitride substrates. The mounting collar is clamped between a shield member encircling the gas pump of the sensor element and a housing member by threaded clamping nuts. The shield member has one or more apertures therein to admit exhaust gases to be analyzed to the gas pump of the sensor element.

Abstract: A process for making an encapsulated metal oxide varistor package comprises pressing the varistor powder mixture into a disc, sintering the pressed disc, followed by slow cooling to room temperature.The sintered disc is acid etched and a fritted-silver electrode applied on each side of the disc or in the alternative an aluminum coating is arc sprayed on each side of the disk followed by an arc sprayed copper coating on top of the aluminum coating. The fritted-silver electrode coating is heated to 660.degree. C. and slow cooled to room temperature. Sn-coated copper leads are soldered on the electroded disc of either electrode process and the assembly is encapsulated in resilient epoxy resin to form the encapsulated metal oxide varistor package.

Abstract: An arc limiting refractory resistive element is fabricated from aluminum oxide, carbon black and a sintering aid. The fabricating process includes compacting a mixture of the materials, sintering the compact in an inert atmosphere, then oxidizing the outer region of the sintered compact to form a non-conductive sheath around the electrically conductive material.

Abstract: An arc limiting refractory resistive element is fabricated from aluminum oxide, carbon black and a sintering aid. The fabricating process includes compacting a mixture of the materials, sintering the compact in an inert atmosphere, then oxidizing the outer region of the sintered compact to form a non-conductive sheath around the electrically conductive material.

Abstract: An arc limiting refractory resistive element is fabricated from aluminum oxide, carbon black and a sintering aid. The fabricating process includes compacting a mixture of the materials, sintering the compact in an inert atmosphere, then oxidizing the outer region of the sintered compact to form a non-conductive sheath around the electrically conductive material.