Insulator (electricity)

About: Insulator (electricity) is a research topic. Over the lifetime, 15941 publications have been published within this topic receiving 108950 citations. The topic is also known as: electrical insulator.

Electron emission device with electron supply layer of hydrogenated amorphous silicon

Abstract: An electron emission device exhibits a high electron emission efficiency. The device includes an electron-supply layer of metal or semiconductor, an insulator layer formed on the electron-supply layer, and a thin-film metal electrode formed on the insulator layer. The insulator layer has a film thickness of 50 nm or greater. The electron-supply layer is made of hydrogenated amorphous silicon. When an electric field is applied between the electron-supply layer and the thin-film metal electrode, the electron emission device emits electrons.

Improvement of the DC voltage insulation efficiency of suspension insulators under contaminated conditions

Abstract: The authors describe the results of the research and development on a suspension-type insulator having a DC contamination withstand voltage 1.25 to 1.3 times higher than that of the standard DC fog insulator, as measured by the fog-withstand or the clean-fog method. Also described are the withstand voltage characteristics of the suspension insulator contaminated with soluble materials and nonuniformly contaminated, simulating natural-field conditions. Design criteria taking these results into account are also discussed. >

Insulation state measurement method, insulation state judgement apparatus, and dispersion type power generating system using the same

Abstract: An object of the present invention is to provide an insulation state measurement method and a judgement apparatus for a power conversion system, which can monitor the insulation state of an electric path with one end to which a power scarce is connected, or the power source itself in a non-use state of the power source, and can prevent an unexpected failure. A solar cell array connected to one end of an electric path is set in a non-grounded state upon operation of a change-over switch, and a measurement switch which receives an operation command from an operating circuit temporarily applies a high voltage to the electric path. A current detector detects a weak current flowing through connection lines, and supplies detection data to an insulation judgement unit. The insulation judgement unit calculates the insulator resistance on the basis of the magnitude of the applied voltage, and the magnitude of the weak current detected by the current detector. If an abnormality is detected, information indicating the abnormality is displayed on a display unit. In this manner, an unexpected failure can be avoided.

Low-voltage field emission from tungsten fiber arrays in a stabilized zirconia matrix

Abstract: Field emitter array cathodes were fabricated from unidirectionally solidified composites of tungsten fibers in an insulating yttria-stabilized-zirconia (YSZ) matrix. A close-spaced molybdenum gate film (extractor) was formed utilizing e-beam evaporation of alumina as an insulator, which was overlayed by the molybdenum extractor. The high resistivity of the composite matrix coupled with the alumina insulator resulted in low leakage current and permitted dc operation of the device. Emission testing demonstrated current densities of 1--5 A/cm/sup 2/ with leakage in the ..mu..A range for applied potentials of 125--200 V. Variation of emitter tip geometries from hemispheres to right circular cylinders to pointed cones produced increases in emission consistent with reduced tip radii.

Field emission at 10Vcm−1 with surface emission cathodes on negative-electron-affinity insulators

Abstract: Surface emission cathodes reported here consist of two electrodes separated by ∼10μm on a negative-electron-affinity glass, Cs2Si4O9. The electrodes consist of a W film suspended over the insulator by a gap of 0–70 nm. When electron emission is initiated with a bias of 0–300 V, between the electrodes, the cathodes continue to emit after the bias is removed and for anode voltages as low as 20 V, electric fields <10Vcm−1. The emission is modeled by the electrons tunneling from the electrode onto the glass surface and from there they are emitted into vacuum. Emission without bias is the result of positive charge in the insulator, which replaces the need for a bias voltage.