Results 171 to 180 of about 968 (215)
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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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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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Phase development in ZnO varistors
Advances in Applied Ceramics, 2014Based on a typical ZnO varistor composition (97·0 mol.-% ZnO, 1·0 mol.-% Bi2O3, 1·0 mol.-% Sb2O3, 0·5 mol.-% MnO and 0·5 mol.-% Co3O4), phase development of the ZnO varistor during sintering has been investigated using in situ high temperature X-ray diffraction up to 900°C, and conventional ambient X-ray diffraction for samples sintered at 900°C to ...
Fan, J, Poosimma, P, Freer, Robert
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Prebreakdown Conduction in ZnO Varistors
Journal of the American Ceramic Society, 1992A model which quantitatively accounts for the important features of prebreakdown conduction in ZnO‐based metal oxide varistors in presented. The prebreakdown current dependence with applied voltage and temperature enables us to extract several features for the grain boundary.
Miriam S. Castro +3 more
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Impulse current withstanding capability of ZnO varistors with influence of varistor size
IEEJ Transactions on Electrical and Electronic Engineering, 2019Through injecting 8/20 and 30/60 μs impulse currents to five kinds of ZnO varistors, the influence of the varistor size on the single impulse current withstanding capability of a ZnO varistor is investigated in this article. A comprehensive damage criterion of a varistor consisting of three aspects, namely, mechanical failure by visual inspection ...
Jianguo Wang +5 more
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Varistor-capacitor characteristics of ZnO ceramics
Journal of Materials Science, 1986Electrical properties of ZnO ceramics quenched from several temperatures during the cooling down from sintering temperature were correlated with microstructural changes. Barrier parameters were determined and their variation was interpreted under the assumption that measured donor densities were due to extrinsic donor defects segregated at grain ...
P. Q. Mantas +2 more
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Ceramic varistors based on ZnO–SnO2
Journal of the European Ceramic Society, 2004Abstract Model ceramic varistor formulations based on 98% ZnO–SnO2 (plus 2% oxides of Bi, Co and Mn) were prepared by conventional powder processing routes; specimens were sintered at 1150–1275 °C. The product density increased with SnO2 content, but decreased with increase in sintering temperature.
A. Anastasiou +3 more
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Rate-controlled shrinkage of ZnO varistors
Journal of Materials Processing Technology, 1996Abstract Shrinkage of ZnO varistors has been controlled during the firing process at a constant rate using a feed back loop to control the heating rate. This was accomplished by developing software which calculates the shrinkage from a signal coming from a displacement transducer, then it compares the current shrinkage rate with a previously set ...
A. Al-Tounsi, R. Puyané, M.S.J. Hashmi
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Impedance and Modulus Spectroscopy of ZnO Varistors
Journal of Electroceramics, 1997The ac response of ZnO varistors has been investigated over thetemperature range 100 to 380°C using impedance and modulusspectroscopy. Impedance spectra show only a single peak, which representsthe most resistive component in the sample and is responsible for the dcproperties, whereas an additional peak appears in the modulus spectrum.
A.R. West, M. Andres-Verges
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