Topic
Saturation current
About: Saturation current is a research topic. Over the lifetime, 3256 publications have been published within this topic receiving 49530 citations.
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TL;DR: In this article, two methods of calculating hysteresis losses in hard superconductors are described and the London model is assumed in which the critical current density is taken independent of magnetic field.
Abstract: Two methods of calculating hysteresis losses in hard superconductors are described. The London model is assumed in which the critical current density is taken independent of magnetic field. Losses in isolated wires of different cross section are considered but it is found that losses for solid wires vary by at most a factor of 3 for different shaped wires of the same current-carrying capacity. The loss at saturation current is usually 0·4-0·6 Ic2μ0/π. Losses at the edges of thin sheets are also calculated and a fourth-power dependence on current (for low current) is found. Three systems are examined: a slit parallel to the current in a wide sheet (Lc similar, equals μ0j2g2π3 F4/24), one pair of the edges of two wide strips set back-to-back and carrying antiparallel currents (Lc similar, equals μ0πj2s2 F4/6) and a long thin wall parallel to the current flow on a wide sheet (Lc similar, equals μ0π3j2a2 F4/3). Lc is the loss per cycle per unit length, F is the current peak as a fraction of saturation current, g the width of the slit, s the spacing of strips, a the height of the asperity and j the critical current density per unit width. All in MKS units.
1,062 citations
TL;DR: In this article, it is shown that atmospheric absorption causes a shift in the solar spectrum which changes the value of the optimum forbidden energy gap between the limits 1.2 ev < 1.6 ev.
Abstract: The theory of the photovoltaic effect is used to predict the characteristics of a semiconductor which would operate with an optimum efficiency as a photovoltaic solar energy converter. The existence of such an optimum material results from the interaction between the optical properties of the semiconductor which determine what fraction of the solar spectrum is utilized and its electrical properties which determine the maximum efficiency of conversion into electricity. Considerable attention is devoted to the effect of the forbidden energy gap (EG) of the semiconductor. It is shown that atmospheric absorption causes a shift in the solar spectrum which changes the value of the optimum forbidden energy gap between the limits 1.2 ev
879 citations
TL;DR: In this paper, the authors investigated the temperature dependence of the performance of solar cells in the temperature range 273 −523 K. The solar cell performance is determined by its parameters, viz., short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), and efficiency (η).
646 citations
TL;DR: In this article, a new state of the art in thin-film polycrystalline Cu(In,Ga)Se2-based solar cells with the attainment of energy conversion efficiencies of 19·5% was reported.
Abstract: We report a new state of the art in thin-film polycrystalline Cu(In,Ga)Se2-based solar cells with the attainment of energy conversion efficiencies of 19·5%. An analysis of the performance of Cu(In,Ga)Se2 solar cells in terms of some absorber properties and other derived diode parameters is presented. The analysis reveals that the highest-performance cells can be associated with absorber bandgap values of ∼1·14 eV, resulting in devices with the lowest values of diode saturation current density (∼3×10−8 mA/cm2) and diode quality factors in the range 1·30 1;20% in thin-film polycrystalline Cu(In,Ga)Se2 solar cells. Published in 2005 John Wiley & Sons, Ltd.
541 citations
TL;DR: In this paper, a semiconductor diode designed to operate as an oscillator when mounted in a suitable microwave cavity is described and analyzed, and it appears possible to obtain over 20 watts of ac power in continuous operation at 5 kmc.
Abstract: This paper describes and analyzes a proposed semiconductor diode designed to operate as an oscillator when mounted in a suitable microwave cavity. The frequency would be in the range extending from 1 to 50 kmc. The negative Q may be as low as 10 and the efficiency as high as 30 per cent. The diode is biased in reverse so as to establish a depletion, or space-charge, layer of fixed width in a relatively high resistance region, bounded by very low resistance end regions. The electric field has a maximum at one edge of the space-charge region, where hole-electron pairs are generated by internal secondary emission, or avalanche. The holes (or electrons) travel across the space-charge layer with constant velocity, thus producing a current through the diode. Because of the build-up time of the avalanche, and the transit time of the holes across the depletion layer, the alternating current is delayed by approximately one-half cycle relative to the ac voltage. Thus, power is delivered to the ac signal. When the diode is mounted in an inductive microwave cavity tuned to the capacity of the diode, an oscillation will build up. It appears possible to obtain over 20 watts of ac power in continuous operation at 5 kmc.
521 citations