Preparation of visible-light-emitting p-n junctions in AlAs
Visible light-emitting p-n junctions formed in AlAs via Zn diffusion into single crystal n- type vapor grown AlAs layers
Ettenberg, M.↗
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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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A measurement of the fast luminescent decays of the MV-50 LED
Fast luminescent decay of silicon light-emitting diode
Sutton, J. F.↗
A reusable prepositioned ATP reaction chamber
Luminescence biometer detects presence of life by means of light-emitting chemical reaction of luciferin and luciferase with adenosine triphosphate (ATP) that occurs in all living cells. Amount of light in reaction chamber is measured to determine presence and extent of life.
Hoffman, D. G.↗
A measurement of the fast luminescent decays of the MV-50 LED.
The fast luminescent decay of the MV-50 GaAs doped Si light-emitting diode has been studied. This diode is found to provide a fast, inexpensive, bright, and convenient light source for the calibration of fast optical timing systems. A simple passive electronic module is described that allows driving the light source directly by a laboratory pulse generator.
Sutton, J. F.↗
Ga/1-x/Al/x/As LED structures grown on GaP substrates.
Ga(1-x)Al(x)As light-emitting diode structures have been grown on GaP substrates by the liquid-phase-epitaxial method. In spite of the large differences in lattice constants and thermal-expansion coefficients, room-temperature efficiencies up to 5.5% in air have been observed for a peak emission of 8500 A. Using undoped GaP substrates, which are transparent to the infrared and red portions of the spectrum, thin structures of Ga(1-x)Al(x)As with large external efficiencies can now be made.
Woodall, J. M.↗
Bio-isolated DC operational amplifier
Possibility of shocks from leakage currents can be reduced by use of isolated preamplifiers. Amplifier consists of battery-powered operational amplifier coupled by means of light-emitting diodes to another amplifier which may be grounded and operated from ac power mains or separate battery supply.
Lee, R. D.↗
An experiment in manipulator control with proximity sensors
Optical proximity sensors were used in a feedback loop to automatically position a manipulator hand for grasping. The experiment was a simplified one, involving two dimensional motion only. Two proximity sensors were mounted on the hand, and control signals derived from their outputs were used to drive the hand vertically and horizontally. The sensors employ a pulsed gallium arsenide light-emitting diode together with a silicon detector. They indicate, without contact, the approximate distance between the manipulator hand and object in the range from 5 to 12 cm. Positioning within approximately + or - 5 mm was observed. Extension of the technique to general three-dimensional control is briefly discussed.
Johnston, A. R.↗
Epitaxial growth of III-V compounds for electroluminescent light sources
The epitaxial growth techniques used in the fabrication of III-V compound electroluminescent devices are reviewed. Both vapor and liquid phase epitaxial techniques are discussed, including the applications of these techniques to well established materials as well as newer materials. The state of the art of light-emitting devices fabricated from members of the III-V compounds and their solid solutions is also reviewed.
Chu, T. L.↗
Tracking with head position using an electrooptical monitor
An electrooptical head-position monitoring system was designed and built and is used in single-axis and three-axis 'hands-off' control tasks. The monitor consists of a transparent plexiglass body-fixed helmet provided with a set of eight silicon photodetectors sensing pitch, roll, and yaw motions of the head. Two light-emitting diodes, attached to the pilot's helmet liner, provide the ac modulated near infrared radiation. Head control is compared with conventional manual control for single-axis and three-axis tracking tasks. Both performance curves and describing functions are presented.
Chouet, B. A.↗
Optical feedback technique extends frequency response of photoconductors
Feedback circuit consists of high-gain light-to-voltage converter with frequency-limited nonlinear photoconductor inside feedback loop. Feedback element is visible light-emitting diode with light-out versus current-in characteristic that is linear over several decades.
Katzberg, S. J.↗
Calibration source for sensitive optical detectors
Light-emitting diode (LED), maintained near room temperature, stabilizes wavelength of emitted light and calibrates photo-optical detectors.
Baugh, B. T.↗
Calibration of image dissector tubes
Technique employs computer-controlled light-emitting diode (LED), precision machined mask, and analog-to-digital coverter (ADC). Computer turns on LED which floods masked face of tube. Intensity pattern, generated as tube is electromagnetically swept, is fed to ADC which controls tube calibration.
Klingman, E. E., III↗
Fast measurement of bacterial susceptibility to antibiotics
Method, based on photoanalysis of adenosine triphosphate using light-emitting reaction with luciferase-luciferin technique, saves time by eliminating isolation period required by conventional methods. Technique is also used to determine presence of infection as well as susceptibilities to several antibiotics.
Chappelle, E. W.↗
Diodes stabilize LED output
Small-signal diodes are placed in series with light-emitting diodes (LED's) to stabilize LED output against temperature fluctuations. Simple inexpensive method compensates for thermal fluctuations over a broad temperature range. Requiring few components, technique is particularly useful where circuit-board space is limited.
Deters, R. A.↗
Pressure Switch Is a Low Cost Battery Indicator
Conventional pressure switch, fabricated by printed-circuit manufacturing techniques, can indicate when charge on battery departs from preset level. Membrane on switch is exposed to internal pressure of battery, which varies according to stored charge. When pressure varies from preset level, switch can turn on a light-emitting diode or similar indicator to warn user that battery is low.
Abita, J. L.↗
Wire-Wrap Chatter Detector
Monitoring circuit responds to changes in resistance as little as 0.1 ohm. Has been used to detect defective wire-wrap connections during thermal and vibration tests. Defect is indicated to operator by light-emitting diode and by increase in count on a two-digit display.
Fisch, G. Z.↗
Detecting Solar-Cell Failures
Circuit identified malfunctioning photovoltaic array. Cell-failure detection circuit compares output of photovoltaic array to control cell. If any module fails, activates light-emitting diode. Circuit could also sound alarm.
Maloney, T. J.↗
Status Panel For Video Cassette Recorders
Central array of light-emitting diodes displays status of 30 video cassette recorders (VCR's) monitoring integrated testing of Space Shuttle. Remote status panel linked to VCR's by one 37-conductor cable. Transistor/ transistor logic chips in interface circuit allow LED array to function without drawing power from VCR control circuits.
Talley, G. L., Jr.↗