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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Modified circuit uses diodes to effectively disconnect the charging resistors from the circuit during the discharge cycle. Result is an efficient parallel charging, high voltage pulse modulator with low voltage rating of components.
Tube diode construction with thoriated tungsten cathode and tubes with barium-system cathodes and with thallium pellets - vapor-filled ceramic thyratons and rectifiers development
Linear pinch driven by rectangular current pulse- forming networks studied by streak photographs and magnetic probe records for discharges in argon
Vapor pressure, anode temperature, and inverse emission effects on thallium filled diode tested with barium cathode
High current electric arc characteristics magnetically driven to supersonic velocities in straight and circular channels
Pinch and parallel-plate discharges, and analysis of anode region of quasi-steady MPD arc
Quasi-steady MPD accelerators current conduction and power loss mechanism investigation through local anode fall voltage and current density measurements at different arc current levels
An investigation is made to establish predictable electric arcs along triggered paths for research purposes, the intended application being the heating of the driver gas of a 1 MJ electrically driven shock tube. Trigger conductors consisting of wires, open tubes, and tubes pressurized with different gases were investigated either on the axis of the arc chamber or spiraled along the chamber walls. Design criteria are presented for successful arc initiation with reproducible voltage-current characteristics. Results are compared with other facilities and several application areas are discussed.
High-current zener diode is connected in series with the positive input terminal of a dc supply to block the flow of direct current until a high-frequency control signal is applied across the zener diode. This circuit controls the switching of large dc signals.
Ring counter dissipates very low power in standby conditions, yet drives high-current loads on a low duty-factor basis. Complementary transistors are used so that in one selected stage both transistors are conducting while the transistors of the other stage are cut off.
High-current, low-voltage silicon switching transistor redesigned for obtaining lowest possible saturation drop
Test panel helps control maximum tolerance level for plating solution contaminants. It provides low, medium, and high-current density areas such as exist in production plating, and plating is examined for uniformity of texture and ductility.
This paper presents some of the technical aspects in the development at the Langley Research Center of an air-cove, dual-wound, single-coil, magnetic-suspension system with one-dimensional control. Overall electrical system design features and techniques are discussed in addition to the problems of control and stability. Special treatment is given to the operation of a dual-wound, high-current support coil which provides the bias fields and superimposed modulated field. Other designs features include a six-phase, solid-state power stage for modulation of the relatively large magnitude control current, and an associated six-phase trigger circuit.
High-current cable developed in liquid helium cooled magnets uses aluminum wire interspersed with the superconductor strands. The aluminum maintains higher electrical conductivity, is light in weight, and has low thermal capacity.
Tin and copper provide high current and switching time capabilities for high-current resettable fuses. They show the best performance for trip current and degree of reliability, and have low coefficients of thermal expansion.
Substrate emitter monolithic inverted transistor structure for low-power high-current gain application
Investigation of hot wire dynamic behavior under high-current heating aimed at a better understanding of the ignition process, using high-speed photographic techniques for visual observation of the bridgewire itself during high current heating. Tests were conducted with Tophet A bridgewires in an air environment, as well as in a cell of distilled water at room temperature, and with a boron-potassium perchlorate-Viton pyrotechnic against the bridgewire behind a Plexiglas window.
The effect of an axial magnetic field on the breakdown voltage of a coaxial system of electrodes has been investigated by earlier workers. For low values of gas pressure times electrode spacing, the breakdown voltage is decreased by the application of the magnetic field. The electron cyclotron radius now assumes the role held by the mean free path in nonmagnetic discharges and the breakdown voltage becomes a function of the magnetic flux density. In this paper the dependence of the formative time lag as a function of the magnetic flux density is established and the feasibility of using a magnetic field for igniting high-voltage, high-current discharges is shown through theory and experiment. With a 36 microfarad capacitor bank charged to 48,000 volts, a peak current of 1.3 x 10( exp 6) amperes in a coaxial type of plasma gun was achieved with a current rise time of only 2 microseconds.