Results 171 to 180 of about 2,053 (224)
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The microstructure of a ZnO varistor material
Journal of Materials Science, 1985The microstructure of a ZnO varistor material has been investigated by a combination of X-ray diffractometry and analytical electron microscopy (SEM, TEM, STEM, EDX). The material was found to consist of: ZnO grains (doped with manganese, cobalt and nickel); smaller spinel grains which hinder the growth of ZnO grains during sintering; intergranular Bi ...
E. Olsson +3 more
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A barrier model for ZnO varistors
Journal of Applied Physics, 1979A model of current transport in ZnO varistors is proposed. The model is a modification of an earlier one suggested by Levine, with the major difference being the inclusion of a thin (?10 Å) ’’disordered’’ layer which separates the single-crystal ZnO grains.
P. L. Hower, T. K. Gupta
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Theory of conduction in ZnO varistors
Journal of Applied Physics, 1979A theory is presented which quantitatively accounts for the important features of conduction in ZnO-based metal-oxide varistors. This theory has no adjustable parameters. Using the known values of the ZnO band gap, donor concentration n0, and low-voltage varistor leakage-current activation energy, we predict a varistor breakdown voltage of ?3.2 V/grain
G. D. Mahan +2 more
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Failure modelling for ZnO varistors
Journal of Materials Processing Technology, 1998Abstract The energy-absorption capability of zinc oxide varistors depends on both the binder burn-out and shrinkage rate of the disc. This paper presents a study of the development of a failure model of a varistor disc with a nominal voltage V nom =5 kV and a diameter of 42 mm manufactured by rate-controlled sintering.
M.D Huda +3 more
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Conduction mechanisms in ZnO varistors
Journal of Applied Physics, 1980The thermionic emission enhanced by barrier lowering and the Zener tunnelling in ZnO varistors are discussed. Capacitance versus voltage, reverse current versus temperature, and 1/f noise measurements have been performed on commercial varistors. A model is proposed from which follows a diffusion voltage VD which is consistent both with the 1/C2 vs V ...
L. K. J. Vanadamme, J. C. Brugman
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MRS Proceedings, 1981
The theory of ZnO varistors has evolved along with the increasingly detailed experimental description [1-2]. The extreme nonlinearity in the currentvoltage curves naturally led the early investigators to suggest the well-known nonlinear mechanisms, such as space-charge limited currents or electron tunneling. Later experiments made these first proposals
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The theory of ZnO varistors has evolved along with the increasingly detailed experimental description [1-2]. The extreme nonlinearity in the currentvoltage curves naturally led the early investigators to suggest the well-known nonlinear mechanisms, such as space-charge limited currents or electron tunneling. Later experiments made these first proposals
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ZnO Varistors for Transient Protection
IEEE Transactions on Parts, Hybrids, and Packaging, 1977ZnO varistors are novel ceramic semiconductor devices used for protection of electronic equipment against transient overvoltages due to switching surges or lightning. This article describes the microstructure, circuit behavior, and operation of ZnO varistors.
L. Levinson, H. Philipp
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Synthesis and characterization of multilayered ZnO/glass/ZnO varistors
AIP Conference Proceedings, 2020Low-voltage surge filters are technologically important for the protection of modern computing and telecommunication systems operating at low voltages. In this context the design and characterization of varistors operating at low voltages constitutes a continuous challenge.
Varsamis, C. P. E. +3 more
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The influence of surfactant on ZnO varistors
Ceramics International, 2007Abstract ZnO varistors with and without surfactant such as sodium dodecyl sulphate (SDS) are prepared by nitrate-combustion process. The samples were identically heat treated and sintered at 1000 °C for 12 h to study the influence of the surfactant on the nonlinear electrical properties of polycrystalline ZnO.
S.R. Dhage, S.C. Navale, V. Ravi
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Defects and degradation in ZnO varistor
Applied Physics Letters, 1996A systematic study of the defects in ZnO has been performed. The two commonly observed levels (L1, L2), located at around 0.15 and 0.24 eV under the conduction band, have been identified as native defects. The deep level transient spectroscopy depth profiling technique is applied on multilayer-chip-type ZnO varistors to determine the distribution ...
Wei-I Lee, Ruey-Ling Young
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