Showing papers on "Insulator (electricity) published in 1968"

Bonding an insulator to an insulator

Abstract: AN IN ORGANIC ELECTRICAL INSULATOR MATERIAL IS BONDED TO ANOTHER INORGANIC INSULATOR MATERIAL BY FORMING A METALLIC FILM ON A SURFACE OF ONE OF THE MATERIALS, PLACING THE METALLIZED FILM SURFACE IN CLOSE CONTACT WITH THE OTHER MATERIAL AND APPLYING AN ELECTRICAL POTENTIAL ACROSS THE MATERIALS PRODUCING A LOW CURRENT THROUGH THE COMPOSITE, THE INSULATOR MATERIALS BEING HEATED TO INCREASE THEIR ELECTRICAL CONDUCTIVITY.

Apparatus for terminating electrical ribbon cable

Abstract: A new termination, with which a miniature ribbon cable can be connected readily to other electrical devices, has adjacent cable conductors connected without fan-out to a connector plate having contacts on opposite sides of a board-like insulator. The cable insulation is removed from the conductors, prior to assembly of the cable with the connector plate, preferably along the entire conductor length that overlies the insulator.

Contact Electrification of Insulators and Its Relevance to Electrets

Abstract: Surface charge densities on electrets are frequently measured by means of lectrodes which can be lifted from the insulator surface; however, electrification of the surface can occur as a result of this contact between electrode and insulator, and this can be a source of difficulty in interpreting the results. In these experiments, measurements have been made on the contact electrification of paraffin, polystyrene, and polyethylene, among other materials, using mercury as the electrode. In these cases it is found that the contact charge exchange decreases with decreasing contamination of the insulator. Under controlled conditions, equilibrium surface charge densities as low as 0.003 nC/cm2 have been observed for paraffin. When the contact event produces both high electric fields and also high local surface potentials, the surface charge causes electrical breakdown during the separation of insulator and electrode. We find that it is useful to "developrd the resulting electrostatic charge distribution by xerographic means. The resultant charge distribution frequently shows the gross patchy structure of Lichtenberg figures previously reported for high voltage discharges to insulators in air.

Tests in Japan on the performance of salt-contaminated insulators in natural and artificial humid conditions

Abstract: The paper describes experimental work carried out at the Shiobara Laboratory on the performance of salt-contaminated insulators in both natural and artificial humid conditions. The purpose was to analyse, in relation to humidity, one type of flashover mechanism caused by salinity deposited on a porcelain surface and absorbed moisture in humid conditions. For natural humid conditions, dew, fog and drizzle were available. Based on experience of natural humid conditions, an artificial test with steam fog permitting the gradual formation of humid conditions, was developed. This method produced a flashover voltage of the insulators similar to that in natural conditions. An antifog-type insulator showed the best performance for the insulators that have similar flashover voltage. However, flashover voltages of the two long-term tests showed a great difference from that of the conventional short-term test. A hypothesis of `danger degree for flashover?, is assumed in order to explain the essential differences between the pollution- test methods and results. The danger-degree concept is a combination of two factors: transfer of salinity and humidity

Electrical connecting device

Abstract: An electric power installation has connection between units such as an alternator and transformer, made by hollow, cylindrical phase conductors of different diameters which are coaxially aligned. The cylinders are enclosed by an outer sheath, the conductors and sheath being isolated from one another by a fluid insulant and held spaced apart by insulators having corrugated surfaces to provide long leakage paths. Each insulator extends between the sheath and inner conductor and is withdrawable through a port in the sheath. The conductors are in joined sections which may include expansion joints.

Thickness fluctuations and electric field penetration in thin metal-insulator-metal structures

Abstract: Taking into account film thickness fluctuations, we compare the effective thickness of thermally oxidized Al2O3 films as determined from capacitance, ionic-current, and tunnel-current measurements. We find that the thickness fluctuations grow with oxidation time and with increasing oxidation temperature; the minimum film thickness, however, remains nearly constant. In interpreting the capacitance measurements we consider the effect of electric field penetration of the electrodes. We obtain the characteristic length for aluminium LAl = 0·72 A. We conclude that m ∗ = m at the lower edge of the conduction band of Al2O3.

Multilayer thick film ceramic hybrid integrated circuit

Abstract: MULTIPLE LAYERS OF PRINTED CONDUCTORS ARE INTERLEAVED WITH LAYERS OF PRINTED GLASSY INSULATOR (OR DIELECTRIC) SO AS TO PROVIDE A GREATLY EXPANDED CIRCUIT CAPABILITY ON A SINGLE SUBSTRATE.

A New Technique for the Study of Electronic Transport in Insulators

Abstract: To avoid the barrier limitation at the injecting electrode and the effect of imperfections in the insulator, a low‐energy ( 2 eV.

Plug for plug nozzles

Abstract: A plug for rocket motor plug nozzles has a shell constructed of a thermally anisotropic material, bulk preoriented pyroltic graphite. The shell material is oriented to serve as both an insulator and as a heat conductor to divert heat to various heat sinks. Resilient fastening means are employed to allow relative movement of parts to minimize the effects of thermal stresses.

Buried metallic film devices and method of making the same

Abstract: ELECTRICAL CONDUCTORS AND FIELD PLATES UTILIZED IN INTEGRATED CIRCUIT COMPONENTS ARE BURIED IN INSULATING MEDIA BY FORMING AN INSULATED FILM ON THE SEMICONDUCTOR SUBSTRATE, DEPOSITING A METAL THEREOVER WHICH IS NONREACTIVE WITH THE INSULATOR AT TEMPERATURES OF THE ORDER OF 1100*C., AND COVERING THE CONDUCTIVE FILM WITH ANOTHER INSULATING FILM. AFTER ALL FABRICATION STEPS FOR THE INTEGRATED CIRCUIT DEVICE ARE COMPLETED, CONTACT TO THE METALLIC LAYER IS MADE BY ETCHING A HOLE THROUGH THE LAST DEPOSITED INSULATING FILM AT ONE POINT WITH AN ETCHANT WHICH IS NONREACTIVE WITH THE METALLIC FILM, AND METALIZING THE DEVICE IN THAT REGION, MAKING CONTACT WITH THE BURIED CONDUCTOR. SUCH BURIED CONDUCTORS MAY BE UTILIZED AS CONDUCTORS IN PRINTED CIRCUIT AND MONOLITHIC SEMICONDUCTOR DEVICES, AS CAPACITOR PLATES, AND AS GATE ELECTRODES IN FIELD-EFFECT TRANSISTORS.

Improvements relating to high voltage electrical insulators

Abstract: 1,113,247. Insulators. A. REYROLLE & CO. Ltd. 27 Nov., 1964 [4 Dec., 1963], No. 48001/63. Heading H2C. Each of a number of units 11 of hollow or dished form, intended to be nested together with their metal cores 12 axially overlapping to form an insulator, consist of a rigid hollow metal core 12 embedded in a layer or coating of insulating material 14. The insulation layer 14 which can include a filler such as titanium dioxide may be formed by immersing the heated core 12 in a fluidized bed of powdered casting resin or by electrostatic depoistion. The metal cores 12 which may be of aluminium have flange portions 12A which when coated with the insulation 14 provide weather sheds 17. The insulator elements are cemented together with a synthetic resin. In another embodiment (Fig. 3, not shown) the metal elements are of generally dish-shaped construction.

Measurements on Insulator-Surface Breakdown in Vacuum Under dc Voltage

Abstract: The breakdown voltage over insulator surfaces in vacuum between plane electrodes has been investigated for different insulator materials and geometries using dc voltage. The spark current as a function of time was measured showing a current rim of 1–2 A/nsec and a slower decay. The spark is followed within a millisecond by weak discharge pulses. The time delay of these pulses indicates that they originate at the cathode.

Excitonic insulator in GaAs junctions.

Abstract: Excitonic insulator formation by electrons and holes pairing in GaAs p-n junctions from electron tunneling data comparison with theory

Performance of solid insulators in vacuum

Abstract: In the last decade considerable research effort has been devoted to the exploitation of vacuum as an insulating medium. The impetus for this work has come mainly from the rapidly expanding technology of high power x-ray tubes, high energy particle accelerators and space exploration. Most of the research endeavour has been devoted to the study of breakdown across vacuum gaps under steady d.c. fields. Comparatively little attention has been given to the problems of solid insulators in vacuum. In any high voltage vacuum device there must be at least one insulator/vacuum interface which is subjected to the full voltage of the device. The physical size of the vacuum enclosure is often determined by the insulation performances of the solid insulator. Insulators are used for the support of high voltage electrodes and in many cases form the vacuum enclosure (e.g. x-ray and accelerator tubes).

Experimental Investigation of the Current Density Distribution in a Simulated MHD Generator

Abstract: In a magnetohydrodynamic generator with segmented electrodes, the Hall effect prevents a homogeneous current distribution in the region of the electrodes. The results of calculations of the current density distribution in an inert gas alkali metal plasma using simplifying assumptions were compared with measurements made in a simulated argon-potassium generator. The gas in the generator channel had a temperature of about 2000°K and a pressure of 1.1 atm. The potassium content was 0.22% by weight. The gas velocity did not exceed 130 m/sec and the magnetic-field strength was held below 4500 gauss. The emf was simulated by applying an electric field of about 15 v across each electrode pair. Measurements of the intensity distribution of the potassium resonance lines permitted conclusions to be drawn with respect to the distribution of electron temperature and thus current density. In general, qualitative agreement with theory was found. The most pronounced deviation from theory occurred near the electrodes, particularly along the insulator between electrodes. The potential distribution measured along the insulator wall was consistent with light-intensity measurements.

Summary of radiation effects on thermionic insulator materials

Abstract: Radiation effects on thermionic insulator materials - evaluation of beryllia, alumina, thoria, zirconia, and yttria

Improvements relating to high voltage electrical insulators

Abstract: 1,240,854. Insulators with finite surface resistance. BRITISH RAILWAYS BOARD. 4 Dec., 1969 [27 Sept., 1968], No. 46038/68. Heading H2C. A synthetic plastics insulator has finite surface resistance provided by a continuous sheet coating forming its outer surface. The value of resistance is chosen to be such that under polluted conditions insulator leakages of 7 milliamperes and less are carried conductively in the surface of the insulator where the pollution is absent or non-conductive, so that surface tracking is inhibited. It is stated that tracking is insignificant for insulator leakage currents greater than 7 milliamperes. The surface resistance may be provided by resin mixed with antimony doped tin oxide. A formula is given relating the minimum current for which tracking is to be permitted to the current in the surface of the unpolluted insulator for a given voltage across it, and from the latter current the required resistance of the surface can be calculated. A correction can be made if the surface resistivity is dependent on the voltage stress in the surface.

The fundamentals of electric breakdown in gases

Abstract: Typically a gas is almost a perfect electrical insulator which allows its widespread use in that capacity. When an electric field of sufficient intensity is applied across a gas, it can become an electrical conductor. The transition from the electrically insulating state to the electrically conducting state is called electric breakdown. This paper is a tutorial attempt to review the fundamental physical processes involved in electric breakdown in gases. The basic processes are presented rather than a complete and encyclopedic review. There are several review articles and books to which the reader can refer for amplification.1–5

Improvements in or relating to visual pattern identification systems

Abstract: 1,130,574. Pattern recognition. PLESSEYUK Ltd. 1 Feb., 1966 [4 Nov., 1964], No. 44970/64. Heading G4R. [Also in Division H1] A visual pattern is impressed upon an array of photo-sensitive elements coupled to integrated logic circuits incorporating gate circuits to produce an electric output representative of the pattern. Light reflected from a printed or written character is focused on to the array, individual elements of which are connected in groups to the logic circuits to recognize particular features (such as straight lines, or particular curves) or whole characters. The logic circuit outputs may punch cards or tape for computer input. Constructional details.-The array of photosensitive elements is part of a sandwich consisting of layers as follows, in order, transparent electrode, photo-conductive layer of cadmium sulphide, forest of conductive rods in insulator, silicon substrate, earthed conductor, insulator, logic circuit input connections, insulator, positive voltage supply conductors arranged mutually parallel, insulator, negative voltage supply conductors mutually parallel but orthogonal to the positive conductors, and insulator. The logic circuits are formed along one edge of the sandwich in an integrated manner as a sandwich of a layer of input terminals, a layer of partially conducting material, a layer of conductive rods in insulator, and a silicon substrate. A modification uses photo-transistors in place of the photo-conductive layer. As a further modification, the logic circuits could be interspersed with the photo-sensitive elements.

Porcelain insulation for EHV equipment and transmission lines

Abstract: Insulators used on high voltage systems are not particularly fragile; but they are, undeniably, brittle. Reasonable familiarity with flaw and fracture theory is prerequisite to an understanding of a brittle material. Consider, for example, the following list which the authors have selected from their subjects and projects of the past year: Analysis of insulator failures, in service or from handling. Gunshot and power arc resistance of suspension insulators. Residual strength of damaged insulators. A method of measuring the “toughness” of ceramic materials. Hydraulic test for suspension insulator shells. Statistical specifications for insulators.1, 2

A fast, room temperature, millimeter and submillimeter electric-tunnel effect detector

Abstract: It is well known that current can flow between two metal electrodes, separated by a thin oxide or insulator layer of the order of 50A thick, by means of the electric-tunnel effect. Estimates have been made that it requires 10-16sec for an electron to tunnel from one electrode to the other. Calculations by Simmons and others have shown that for low voltages dissimilar electrode junctions are to a first approximation ohmic. We show in this paper that to a second approximation an asymmetry square law dependence appears for an ideal trapezoidal barrier, Which can lead to detection. The I-V curves and responsivity (volts/watt) of the detector are calculated for typical parameters.

Variable resistance information reading element

Abstract: A recording device in which there is added in accordance with a recording signal an impurity acting as a recombination center and forming a deep energy level to a solid like a semiconductor and an insulator having a forbidden band in their energy band structures and applying an elastic wave to said solid so that the electric resistance in the neighborhood of the impurity atoms is varied thereby converting the recorded signal to an electric signal.

Ionic mobility in the insulator layer of thin film transistors

Abstract: : The mobility of the instability inducing ions in the SiO-SiO2 layer of vacuum deposited FETs has been estimated to be about 0.000001 cm sq/V sec. (Author)