Push test for switch welds
Pencil-like tool that applies low predetermined force, may be used to individually test switch welds for identification of poor or marginal welds without harming good ones.
Torborg, C. J.↗
SEARCH · Engineering Papers
Results for “switches”
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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Minimizing spikes in switching-regulator circuits
Circuit, employing tapped inductor to back-bias rectifying diodes and extra diode to cummutate current, minimizes current spikes that cause premature transistor failure in switching-regulator circuits.
Mclyman, W. T.↗
Automatic thermal switch
Automatic thermal switch closes and opens heat-flow path in response to temperature changes. Control is used to regulate temperature in electronic circuitry or cryogenic refrigeration equipment.
Cunningham, J. W.↗
JANTX/N1202A switching diode
General Electric and International Rectifier switching diodes were tested. Group 2 testing proved to be most damaging to both lots. In group 2 testing many visual failures were seen in samples from both manufacturers.
Source record↗
JANTX1N5552 switching diode
Switching diodes manufactured by Micro Semidonductor and Semtech were tested. In groups 2 and 3 there were no Micro Semiconductor catastrophic failures. Testing of both lots was stopped in group 1 test because of 50% failure rate.
Source record↗
Switching reduces computer power requirement
Network of power switches activates only selected TTL circuits necessary for that particular time interval. Power that was fed to inactive circuits and dissipated is no longer applied. Because of this, system can use much higher, smaller power source.
Source record↗
A dc model for power switching transistors suitable for computer-aided design and analysis
A model for bipolar junction power switching transistors whose parameters can be readily obtained by the circuit design engineer, and which can be conveniently incorporated into standard computer-based circuit analysis programs is presented. This formulation results from measurements which may be made with standard laboratory equipment. Measurement procedures, as well as a comparison between actual and computed results, are presented.
Wilson, P. M.↗
Computer-aided analysis and simulation of switched dc-dc converters
State space techniques are employed to derive an equivalent nonlinear recurrent time-domain model that describes the switched dc-dc converter behavior exactly. This model is employed effectively to analyze both large signal behavior by propagating the recurrence equation and matching boundary conditions through digital computation and small signal behavior by linearizing it about the equilibrium state.
Lee, F. C.↗
Predicting performance of power converters operating with switching frequencies in the vicinity of 100 kHZ
A model describing the turning-on period of a power switching transistor in an energy storage voltage step-up converter is presented. Comparisons between an experimental layout and the circuit model during the turning-on interval demonstrate the ability of the model to closely predict the effects of circuit topology on the performance of the converter. A phenomenon of particular importance that is observed in the experimental circuits and is predicted by the model is the deleterious feedback effect of the parasitic emitter lead inductance on the base current waveform during the turning-on interval.
Bahler, D. D.↗
Modeling of switching regulator power stages with and without zero-inductor-current dwell time
State-space techniques are employed to derive accurate models for the three basic switching converter power stages: buck, boost, and buck/boost operating with and without zero-inductor-current dwell time. A generalized procedure is developed which treats the continuous-inductor-current mode without dwell time as a special case of the discontinuous-current mode when the dwell time vanishes. Abrupt changes of system behavior, including a reduction of the system order when the dwell time appears, are shown both analytically and experimentally. Merits resulting from the present modeling technique in comparison with existing modeling techniques are illustrated.
Lee, F. C. Y.↗
Multipath star switch controller
Device concept permits parallel computers to scan several commonnetwork-connected data stations at maximum rate. Sequencers leap-frog to bypass ports already being serviced by another computer. Two-path system for 16-port star switch controller is cost effective if added bandwidth or increased reliability is desired. Triple-path system would be cost effective for 32-port controller.
Anderson, T. O.↗
Fast microwave switching power divider
Unit divides power from single input among any 12 of 120 output terminals and redistributes it in 6 microseconds. Microwave current from coaxial line excites disk feeding many radial strip transmission lines. Built for use in electronically-steered S-band antenna, device also divides and switches energy among filters and phase shifters.
Johnson, R. W.↗
Heat switch has no moving parts
No moving parts are needed for thermally actuated switch. It could also operate as variable thermal conductance, allowing temperature of equipment to be regulated with minimal expenditure of energy.
Castles, S. H.↗
Time-sharing switch for vacuum brazing
Switching unit changes power and cooling-water connections between two vacuum-brazing machines. It allows both units to be powered by single radio-frequency (RF) generator. One machine can be used for brazing while bell jar of other is being evacuated (20 minute process) in preparation for brazing or is being cooled after brazing (10 minute process).
Stein, J. A.↗
Solid-state switch modeling
A model for predicting voltages and currents of passive loads during turn on and turn off of remote power controllers is presented. The model is concerned with two devices, a five ampere device and a twenty ampere device. The model is presented as a general circuit diagram. The load current is determined by the load parameters and the conditions at switching and the steady state conditions are reached according to time constants determined by the load. The model is used to analyze the turn on and turn off conditions of certain loads including a R-C load and a R-L load.
Raburn, W. D.↗
An adaptive-control switching buck regulator - Implementation, analysis, and design
Describing-function techniques and averaging methods have been employed to characterize a multiloop switching buck regulator by three functional blocks: power stage, analog signal processor, and pulse modulator. The model is employed to explore possible forms of pole-zero cancellation and the adaptive nature of the control to filter parameter changes. Analysis-based design guidelines are provided including a suggested additional RC-compensation loop to optimize regulator performances such as stability, audiosusceptibility, output impedance, and load transient response.
Lee, F. C.↗
A dc model for power switching transistors suitable for computer-aided design and analysis
The proposed dc model for bipolar junction power switching transistors is based on measurements which may be made with standard laboratory equipment. Those nonlinearities which are of importance to power electronics design are emphasized. Measurements procedures are discussed in detail. A model formulation adapted for use with a computer program is presented, and a comparison between actual and computer-generated results is made.
Wilson, P. M.↗
Specifying capacitors for performance and reliability in switching power supplies
The three most commonly used switching circuits are the full bridge converter, the half bridge converter, and the forward converter. All three circuits use the same pulse width concept for regulation with the major difference being how many transistors are used for power handling. The full bridge uses four transistors, the half bridge uses two, and the forward converter uses one. In practical design, forward converters are used at 300 watts and below, half bridges at 300 to 600 watts, and full bridges above 600 watts. Regulation is achieved by alternately saturating diagonal pairs of transistors in the full bridge, alternately saturating transistors in the half bridge, and simply pulse modulating one transistor in the forward converter.
Greenhalgh, F. E.↗