Increasing Voltage Levels Research Articles

Measuring the upset of CMOS and TTL due to HPM-signals

Abstract. To measure the performance of electronic components when stressed by High Power Microwave signals a setup was designed and tested which allows a well-defined voltage signal to enter the component during normal operation, and to discriminate its effect on the component. The microwave signal is fed to the outside conductor of a coaxial cable and couples into the inner signal line connected to the device under test (DUT). The disturbing HF-signal is transferred almost independent from frequency to maintain the pulse shape in the time domain. The configuration designed to perform a TEM-coupling within a 50 Ohm system prevents the secondary system from feeding back to the primary system and, due to the geometrical parameters chosen, the coupling efficiency is as high as 50–90%. Linear dimensions and terminations applied allow for pulses up to a width of 12ns and up to a voltage level of 4–5 kV on the outside conductor. These pulse parameters proved to be sufficient to upset the DUTs tested so far. In more than 400 measurements a rectangular pulse of increasing voltage level was applied to different types of CMOS and TTL until the individual DUT was damaged. As well the pulse width (3, 6 or 12 ns) and its polarity were varied in single-shot or repetitive-shot experiments (500 shots per voltage at a repetition rate of 3 Hz). The state of the DUT was continuously monitored by measuring both the current of the DUT circuit and that of the oscillator providing the operating signal for the DUT. The results show a very good reproducibility within a set of identical samples, remarkable differences between manufacturers and lower thresholds for repetitive testing, which indicates a memory effect of the DUT to exist for voltage levels significantly below the single-shot threshold.

Pathway phase waveform characteristics correlated with length and rate of stylet advancement and partial stylet withdrawal in AC electrical penetration graphs of adult whiteflies

AbstractA technique was developed for measuring the length of stylet insertion during adult whitefly probing. The distance that the labium shortens during a probe was shown to be equal to the length of stylets that were inserted into the plant tissue. The length of labial shortening then was measured in high‐magnification video recordings of adult female silverleaf whitefly, Bemisia argentifolii, in conjunction with recording electrical penetration graphs (EPGs – AC method). Using a split‐screen device, video images of the whitefly's labium during a probe and the EPG waveforms produced during the probe were recorded simultaneously on the same video tape. On playback, changes in labial length could be measured during specific EPG waveforms to determine the length of stylet insertion that occurred during the waveforms. The focus of the study was on two characteristics of the pathway phase sawtooth waveform: the frequency of voltage peaks and the increase in voltage level that occurs over time during sawtooth waveforms. The rate of stylet penetration was significantly and positively correlated with frequency of sawtooth waveform voltage peaks (r2= 0.33) and the length of stylet penetration was significantly and positively correlated (second‐order polynomial) with the relative difference in voltage level between the beginning and end of the sawtooth waveform (r2= 0.43). Stylet advancement did not appear to occur during the few low‐flat waveforms (unknown behavioral correlation) and high‐flat waveforms (phloem phase) that were observed. Voltage drops occur sporadically during sawtooth waveforms, and these were associated with partial stylet withdrawal (indicated when the labium increased in length, but the probe was not terminated) with an accuracy of 99%.

Linear and nonlinear waves in edge channels.

We have studied edge magnetoplasmons confined in the edge channels of a two-dimensional electron gas by analyzing the response of a voltage pulse at different distances from the excitation point. The transition from linear to nonlinear response with increasing voltage level is investigated as a function of the magnetic field (filling factor), the polarity of the applied pulse, and the temperature. Damping originates from the penetration of the wave into the bulk of the two-dimensional system which depends strongly on the width of the incompressible strips. The observed strong increase of the damping with temperature results from the smearing of the restricting incompressible strip. In the nonlinear regime the formation of shock waves can be observed.

LARGE-SIGNAL ANALYSIS OF IN P IMPATT DIODES WITH PROPOSED APPLICATIONS TO AIRBORNE-RADAR SYSTEMS

The purpose of this paper is to provide a better understanding of the effects of the operating conditions on the performance of the high effeciency In P-IMPATT diodes. These effects are investigated using the full-scale computer simulation of these devices. The simulation takes fully into account all the physical effects pertinent to the IMPATT diode operation. It is found that by increasing the RF-voltage level across the diode terminals, three different modes of operation can be obtained successively. The first one is the conventional IMPATT mode. The second one is .a high-effeciency mode. In this mode, the avalanche-generated pulse (AGP) is bunched and accelerated during the second half cycle causing the induced current Ji to increase . In the third mode, which is also a high effeciency one,the AGP is prematurely collected. It is found that by increasing the operating frequency ,the premature collection of the AGP is either delayed or suppresed but the bunching and acceleration of this pulse become less pronounced. It is found that by increasing the DC-bias current, the premature collection of the AGP is either delayed or suppressed whereas the acceleration and bunching of this pulse are inhanced. On the other hand,the trapping of electrons behind the AGP becomes more significant. It is demonstrated that the optimum values of both the DC-bias current and the RF voltage level increase with the operating frequency. The possible applications• of the In P IMPATT diodes to airborne radar systems are indicated.

Field optimisation of high-voltage electrodes

Stresses on materials for HV components have become increasingly large owing to the reduction of their size and the worldwide increase in voltage levels. Since the electrical stress depends heavily on geometric factors, critical domains of an arrangement cannot be represented by such simple bodies as rings, spheres or cylinders. The paper describes an algorithm based on the CAD concept for optimising electrode contours according to given field distributions on their surfaces. This algorithm strictly separates field calculations and geometric corrections. The curvature change necessary to alter the contour is obtained by the simultaneous displacement of all contour points. Using this method, for example, a constant and minimum field strength, or a maximum initial voltage in air or SF6, is achieved. Tests were run on several HV components designed for practical use. The experimental results demonstrated the improvements predicted by the computer calculations.

Perception of two-component electrocutaneous stimuli.

Electrocutaneous stimuli varying in strength (6, 8, 10 V) and frequency (9, 27, 81 Hzj were presented in pairs. Subjects were asked to give a numerical score to represent their perception of overall difference in a pair. To assess their ability to use numbers and their performance on unfamiliar stimuli, no guidance on the nature of the stimuli or the range or scale of the scores was given. Dimensional analysis indicated that perception of differences in one component was influenced by the absolute level of the other component, if this was constant in the pair, or by the difference. Considerable variation among subjects in the nature and extent of this interference effect was observed. Individual differences scaling (INDSCAL) enabled a satisfactory consensus model to be obtained. An empirical relationship expressing the observed twocomponent difference scores in terms of one-component scores was derived. Increasing voltage level diminished perception of frequency difference. Higher frequency levels augmented perception of voltage difference. This relationship is a modification of the combinatorial model proposed by Krantz and Tversky (1975). Individual differences in the combinatorial process are allowed for by application of the subject weightings from the INDSCAL solution.

Transient Response of a Floor Net Used as Ground Return in High Voltage Test Areas

As the test voltage level increases, it becomes more and more difficult to protect the control and measuring cables from the disturbances generated during the tests. To cope with this problem, new high voltage laboratories are nowadays equiped with a copper floor net used as ground return. This paper presents a theoretical analysis of the transient response of such a ground return system. The calculated performances compare favorably with experimental results obtained with the ground return system of the high voltage laboratory at IREQ, and can apply to the selection of the proper ground return system in new high voltage test areas.