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Showing papers on "Electromagnetic compatibility published in 1998"


Journal ArticleDOI
TL;DR: Several aspects of the calculation of lightning electric and magnetic fields in which return stroke models are used to specify the source are considered, including equations for fields and channel-base current, as well as a discussion of channel tortuosity and branches.
Abstract: Four classes of models of the lightning return stroke are reviewed. These four classes are: (1) the gas dynamic models; (2) the electromagnetic models; (3) the distributed-circuit models; and (4) the "engineering" models. Validation of the reviewed models is discussed. For the gas dynamic models, validation is based on observations of the optical power and spectral output from natural lightning. The electromagnetic, distributed-circuit, and "engineering" models are most conveniently validated using measured electric and magnetic fields from natural and triggered lightning. Based on the entirety of the validation results and on mathematical simplicity, we rank the "engineering" models in the following descending order: MTLL, DU, MTLE, BG, and TL. When only the initial peak values of the channel-base current and remote electric or magnetic field are concerned, the TL model is preferred. Additionally discussed are several issues in lightning return-stroke modeling that either have been ignored to keep the modeling straightforward or have not been recognized, such as the treatment of the upper, in-cloud portion of the lightning channel, the boundary conditions at the ground, including the presence of a vertically extended strike object, the return-stroke speed at early times, the initial bi-directional extension of the return stroke channel, and the relation between leader and return stroke models. Various aspects of the calculation of lightning electric and magnetic fields in which return stroke models are used to specify the source are considered, including equations for fields and channel-base current, as well as a discussion of channel tortuosity and branches.

529 citations


Journal ArticleDOI
TL;DR: In this article, the dominant high-frequency current paths are identified, and this allows the oscillation frequencies to be predicted from knowledge of the component values, and the analysis is confirmed using laboratory measurements.
Abstract: Stray components distributed in a pulsewidth modulation (PWM) drive system form parts of resonant circuits which can be excited to produce radio frequency (RF) noise driven by the pulsed switching action of the power devices. The dynamic response of such circuits is complex. It is essential to identify the dominant oscillation modes in the system so that electromagnetic interference (EMI) reduction techniques can be effectively implemented. This paper (Part I) investigates the mechanisms of conducted EMI emissions associated with a typical PWM inverter induction motor drive system. A numerical model, which includes the high-frequency effects within the machine, is established to evaluate the emissions in the time domain. The dominant high-frequency current paths are identified, and this allows the oscillation frequencies to be predicted from knowledge of the component values. The analysis is confirmed using laboratory measurements. Simplified frequency domain methods for direct calculation of the emission spectra based on the dominant high-frequency current paths are discussed in Part II.

258 citations


Journal ArticleDOI
TL;DR: In this article, coordinated lightning current and field measurements are performed at the telecommunication tower on the mountain Hoher Peissenberg in the south of Germany, and detailed waveforms of the lightning currents and corresponding magnetic fields as well as their respective derivatives are described.
Abstract: In order to protect electronic devices against the effects of lightning strikes to tall structures, detailed information about the lightning currents and the radiated electromagnetic fields are necessary For this purpose, coordinated lightning current and field measurements are performed at the telecommunication tower on the mountain Hoher Peissenberg in the south of Germany The instrumentation is described Of special interest are the detailed waveforms of the lightning currents and the corresponding magnetic fields as well as their respective derivatives Electronic systems are mainly affected by the impulse current components in a lightning strike to a tall structure The lightning current and corresponding field waveforms are discussed and detailed statistical evaluations of different parameters are presented

80 citations


Journal ArticleDOI
TL;DR: In this article, a partial element equivalent circuit (PEEC) model for the analysis of the electromagnetic environment inside a building during a direct or nearby lightning strike was proposed for the lightning protection system (LPS).
Abstract: This paper proposes a partial element equivalent circuit (PEEC) model for the analysis of the electromagnetic environment inside a building during a direct or nearby lightning strike A PEEC model for the lightning protection system (LPS) is developed in conjunction with a PEEC model for braided coaxial cables A two-step matrix solution of the whole set of equations describing the LPS and cables allows one to predict the current distribution in the downconductors and the induced voltages and currents on the cables' shield and loads Results are given in frequency and time domain for direct and nearby lightning strikes and for different positions of the cables inside the LPS volume

48 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe an efficient algorithm based on moment-matching techniques for simulation of high-speed circuits in the presence of electromagnetic interference (EMI) using complex frequency hopping (CFH) technique.
Abstract: This paper describes an efficient algorithm based on moment-matching techniques for simulation of high-speed circuits in the presence of electromagnetic interference (EMI). The proposed method is based on the recently developed complex frequency hopping (CFH) technique for interconnect analysis. The new technique is useful for susceptibility analysis and is two to three orders of magnitude faster than conventional simulation techniques. In addition, it can be extended to the analysis of interconnects with frequency-dependent parameters and nonlinear terminations.

46 citations


Journal ArticleDOI
TL;DR: In this paper, the characteristics of the electromagnetic spectrum caused by partial discharges (PDs) in air at three different types of high-voltage substations were investigated and the electromagnetic noise spectrum was characterized depending on the type of substation.
Abstract: The authors investigated the characteristics of the electromagnetic spectrum caused by partial discharges (PDs) in air at three different types of high-voltage substations. From the measured results, they characterized the electromagnetic noise spectrum depending on the type of substation. They also measured the long-term change of the average gain of the noise spectrum and discussed the influence of atmospheric conditions on the results. Moreover, they introduced the "equivalent charge (q/sub e/)" which was derived by converting the electric field strength estimated from the average gain into the charge magnitude of PD. They also proposed a "phase gate control method" for better understanding the electromagnetic noise spectrum characteristics and the mechanism causing electromagnetic waves from PDs.

42 citations


Journal ArticleDOI
L. Cappetta, M. Feo1, Vincenzo Fiumara1, Vincenzo Pierro1, M. Pinto1 
TL;DR: In this paper, a simple model of mode-stirred electromagnetic reverberating enclosures is proposed and extensive numerical simulations reveal consistently that spatial-field homogenization and deterministic chaos occur together, as the time-harmonic peak displacement of the modestirring wall becomes comparable to the electromagnetic wavelength.
Abstract: We study a simple (ray optical, scalar) model of mode-stirred electromagnetic reverberating enclosures. Extensive numerical simulations reveal consistently that spatial-field homogenization and (wide-sense) deterministic chaos occur together, as the time-harmonic peak displacement of the mode-stirring wall becomes comparable to the electromagnetic wavelength. Reverberation properties can thus be synthetically gauged by Lyapounov exponents. Semiquantitative design optimization criteria are obtained and possible generalizations are discussed.

40 citations


Proceedings ArticleDOI
21 Jun 1998
TL;DR: In this paper, an electromagnetic disturbance model is introduced for stability analysis and augmentation of any digitally implemented control law, composed of a Markovian exosystem supplying radiation events to a discrete-time jump linear system which models how the radiation interferes with the nominal operation of the closed-loop system.
Abstract: High intensity electromagnetic radiation has been demonstrated to be a source of computer upsets in commercially available digital flight control systems. In this paper we introduce an electromagnetic disturbance model which can be used for stability analysis and augmentation of any such digitally implemented control law. The model is composed of a Markovian exosystem supplying radiation events to a discrete-time jump linear system which models how the radiation interferes with the nominal operation of the closed-loop system. We discuss how this model can be used to characterize stability and how it can be parametrized and validated in an experimental setting.

37 citations


Journal ArticleDOI
TL;DR: In this article, a parametric analysis of the influence of the lightning protection system on the output functions is carried out in the frequency domain, which allows one to take into account the probabilistic nature of the input function, which transforms the values of the outputs from a deterministic to a distribution of probability.
Abstract: This paper defines a systematic approach considering the lightning current at the base of the channel as the input function, and the spatial distribution of the electromagnetic (EM) field inside the building, or the overvoltages induced at the open ends of loops as the output functions. A parametric analysis of the influence of the lightning protection system on the output functions is carried out in the frequency domain. The systematic approach allows one to take into account the probabilistic nature of the input function, which transforms the values of the outputs from a deterministic to a distribution of probability. This is extremely useful for all electromagnetic compatibility (EMC) engineers dealing with realistic systems' designs or maintenance problems.

35 citations


Proceedings ArticleDOI
24 Aug 1998
TL;DR: In this article, the authors compare the experimental data and the maximum to mean ratio predicted from statistical theory in a reverberation chamber with a measurement of the mean field at the monitor location.
Abstract: Among the significant characteristics of the electromagnetic environment in a reverberation chamber are isotropy and homogeneity. These characteristics permit robust immunity testing without moving the equipment-under-test or the field generating antenna. However, the statistical nature of the electromagnetic environment gives rise to questions about the ability to predict the test fields at the equipment-under-test. The first issue is the ability to predict and/or establish the maximum test field. The second issue is the ability to predict the field at the equipment-undertest based on a measurement at the monitor antenna/probe location which is in the working volume but remote from the equipment-under-test. This paper extends the comparison of experimental data and the maximum to mean ratio predicted from statistical theory. The paper also compares measured data to theoretical predictions for the maximum field at arbitrary locations within a reverberation chamber based on a measurement of the mean field at the monitor location.

35 citations


Proceedings ArticleDOI
24 Aug 1998
TL;DR: In this paper, current probes have been used by EMC engineers for measuring common mode currents to track down EMC problems for many years, and new uses and ways to extend probe performance are presented.
Abstract: Current probes have been used by EMC engineers for measuring common mode currents to track down EMC problems for many years. Based upon analysis of current probe operation, new uses and ways to extend probe performance are presented. Methods discussed include relative phase measurements, extended low frequency performance, and direct measurement of conductor voltage drop.

Journal ArticleDOI
TL;DR: A computer-aided tool for the design of switching power supplies integrating a layout editor, autorouter, component library builder and EMI simulator is presented.
Abstract: A computer-aided tool for the design of switching power supplies integrating a layout editor, autorouter, component library builder and EMI simulator is presented. The software takes on a modular approach and develops the printed circuit board (PCB) layout with emphasis on electromagnetic compatibility (EMC). The prediction of interference level is achieved by SPICE simulation with suitable model assignments of EMI sources, components, and PCB tracks. An offline forward power converter is built and measured to verify the simulated result. Finally, a performance index is introduced to act as an indicator for the EMC performance of a given PCB layout.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed an approach to improve the lightning protection of sensitive electronics against lightning by injecting currents into the installation or into relevant parts of the installation, so that inductive effects determined the current distribution.
Abstract: The classical lightning conductor, which must prevent fire, has to have a sufficiently small resistance. An analogous condition can be formulated for the new challenge: the protection of sensitive electronics against lightning. In this case, the so-called transfer impedance, which gives the interference voltages across a sensitive input per ampere lightning current, must be made small. The arguments for this approach are described. A theoretical description is available and practical experience has been built up over the years, also in high-voltage (HV) research and in power engineering measurements in the field. This approach was used to greatly improve the lightning protection of several installations: a marine radio station, the peripheral equipment of a nuclear power plant, and an electronic siren for a nationwide public warning system. Detailed investigations were requested by our contract partners, together with suggestions for economically acceptable improvements that could be carried out in reasonable time. Later, the correctness of the renovations had to be demonstrated. In the validation measurements, we injected currents into the installation or into relevant parts thereof. The current waveform was chosen fast enough so that inductive effects determined the current distribution. At present, lightning position and tracking system (LPATS) data on lightning strikes near the marine radio station and the nuclear power plant are available to verify the effectiveness of the protection. After our improvements no more damage was reported.

Proceedings ArticleDOI
24 Aug 1998
TL;DR: In this paper, the authors describe the design of a Helmholtz coil that is a candidate test apparatus for low frequency magnetic field susceptibility testing on military equipment and subsystems, and present practical analytical expressions that may be used to design a helms coil for this unique application.
Abstract: This paper describes the design of a Helmholtz coil that is a candidate test apparatus for low frequency magnetic field susceptibility testing on military equipment and subsystems. Use of this coil would reduce electromagnetic compatibility (EMC) qualification test time, and subject the equipment under test (EUT) to a relatively uniform field which is representative of the actual electromagnetic environment on some naval platforms. Specifically, this paper presents practical analytical expressions that may be used to design a Helmholtz coil for this unique application. Experimental test results for a three foot diameter coil are presented, including: maximum magnetic flux density vs. frequency, impedance vs. frequency, resonant frequency behavior and the effect of coil separation distances greater than one radius.

Book
01 Jan 1998
TL;DR: In this article, the authors present a PCB Layout Guidelines for High Speed Circuit Layout Design Software Appendices Glossary References, including the following: Passive Components Active Discrete Components Integrated Circuits Electromechanical and Hybrid Components
Abstract: Introduction Passive Components Active Discrete Components Integrated Circuits Electromechanical and Hybrid Components General PCB Layout Guidelines High Speed Circuit Layout Design Software Appendices Glossary References.

Patent
Alexis Dubrovin1, Billot Gerard1
24 Sep 1998
TL;DR: In this article, the authors proposed a method for ensuring electromagnetic compatibility for discharge lamp headlights by using a mask made of conductive material and connected to a fixed potential to capture the parasitic electromagnetic fields emitted forwards from the lamp.
Abstract: A motor vehicle headlight comprises a mirror having mounted therein a discharge lamp, a mask placed in front of the lamp, and a shielding plate of conductive material extending behind the mirror. The mask is made of conductive material and is connected to a fixed potential to capture the parasitic electromagnetic fields emitted forwards from the lamp. According to the invention, the shielding plate is constituted by a cover extending behind and along the mirror and connected to said fixed potential. The invention is applicable to ensuring electromagnetic compatibility for discharge lamp headlights.

Journal ArticleDOI
TL;DR: The predicted EM radiation has been validated experimentally and results showing good agreement are presented, and the reliability of the CCAD package is investigated and presented.
Abstract: This paper presents a composite computer-aided design (CCAD) package for prediction of electromagnetic (EM) radiation from a printed circuit board (PCB) at the design stage of equipment. Such a CCAD package has been developed by combining an EM computation tool such as numerical electromagnetic code (NEC)-2, with other circuit design packages (CDPs). The method of prediction of EM radiation using the CCAD is well described in this paper. The predicted EM radiation has been validated experimentally and results showing good agreement are presented. Finally, the reliability of the CCAD package is investigated and presented.

Journal ArticleDOI
12 Oct 1998
TL;DR: In this article, the authors proposed an efficient numerical technique to evaluate the radiated emissions due to a PDS, taking into account the radiation from intentional apertures (i.e., those for ventilation).
Abstract: Power conversion systems and in particular power drives are now present in a large number of applications and environments. The switching operations of power drive systems (PDS) are sources of radiated and conducted electromagnetic interferences that give rise to problems of electromagnetic compatibility with other systems. This work proposes an efficient numerical technique to evaluate the radiated emissions due to a PDS, taking into account the radiation from intentional apertures (i.e. those for ventilation). The power section of the PDS is simulated by a combination of radiating dipoles in which the current is known. The radiated EM field induces currents on the PDS metallic cage surface that in turn radiate outside the cage. These currents are computed by an efficient numerical method known as partial element equivalent circuit technique. Finally an equivalent EM model for the apertures needed for the air cooling and ventilation of the device is given. The proposed prediction model is hence able to predict the total radiated emission from a PDS in its design stage in order to fulfil the electromagnetic compatibility requirements called by the international standards.

Journal ArticleDOI
TL;DR: In this paper, the authors describe a spherical near-field facility set up at the Centre d'Etudes de Gramat (CEG) to perform low-power microwave coupling assessments.
Abstract: This paper describes a spherical near-field facility set up at the Centre d'Etudes de Gramat (CEG) to perform low-power microwave coupling assessments. Specifically, this facility has been designed to determine the coupling cross section of a complex object. However, it can also be used for the characterization of any radiating system in electromagnetic compatibility (EMC) or high-power microwave (HPM) environments. The near-field approach is shown to be complementary and to offer increased flexibility when compared to other more conventional measurement techniques. More particularly, the use of a probe array in the upper part of the frequency band significantly speeds up the near-field measurement process. Consequently, broadband and multiparameter acquisitions can be performed within acceptable duration. The examples given in this paper provide a broad illustration of the capabilities of near-field techniques for EMC and HPM applications.

Book ChapterDOI
01 Jan 1998
TL;DR: This exceptionally ""readable"" text ties together the various related topics in a logical development, and the material flows from the fundamentals of electromagnetic fields to areas of practical application.
Abstract: "Now, in a single convenient volume, you can have all the information you need on real-world applications of electromagnetic theory, including the prediction, analysis, and measurement of electromagnetic fields and their effects. RADIO FREQUENCY PRINCIPLES and APPLICATIONS will guide you from the basics of electromagnetic theory to the full range of new and vital applications. Author Albert A. Smith, Jr. provides a wealth of practical information in an accessible style, without using obtuse theory or requiring complex mathematical derivations. This exceptionally ""readable"" text ties together the various related topics in a logical development, and the material flows from the fundamentals of electromagnetic fields to areas of practical application. The numerous figures provide helpful illustrations, and the appendicies offer additional mathematical details. This book will be of particular use to engineers working in the many diverse fields relating to the a plication of electromagnetic concepts, including engineers involved in RF technology, EMC, radio wave propagation, antennas, radio frequency environments, wireless communications, microwaves, and space systems. Professors: To request an examination copy simply e-mail collegeadoption@ieee.org." Sponsored by: IEEE Electromagnetic Compatibility Society, IEEE Microwave Theory and Techniques Society.

Patent
27 May 1998
TL;DR: In this paper, an electrical model railway set is used to achieve increased electromagnetic compatibility by using AC motors without commutator and slip ring as drive motors for the model vehicles, wherein a simple structure of drive and drive control is attained by performing pulse control of polyphase stator windings of the AC motors of the model vehicle while employing the multi-channel control which is moreover customary in model railway sets.
Abstract: In an electrical model railway set, increased electromagnetic compatibility is achieved by using AC motors without commutator and slip ring as drive motors for the model vehicles, wherein a simple structure of drive and drive control is attained by performing pulse control of polyphase stator windings of the AC motors of the model vehicles while employing the multi-channel control which is moreover customary in model railway sets.

Proceedings ArticleDOI
24 Aug 1998
TL;DR: From this comparison, the authors observe that an on-chip interconnect may generate significantly more radiation than a microstrip track of comparable length, and packaging effects play a major role in this.
Abstract: This paper focuses on the radiated EMC-behaviour of ICs and ASICs. An EMC testchip has been developed, encompassing some passive IC interconnection structures. Together with a dedicated EMC-testboard for mounting the IC, as well as a suited EMC measurement set-up, a configuration is obtained that enables one to perform an in-depth evaluation of some important EMC radiating mechanisms at chip level. The EMC-measurements have focused on the comparison between the radiation from IC-interconnects, and the radiation from well-known PCB-interconnects (such as microstrips). From this comparison, the authors observe that an on-chip interconnect may generate significantly more radiation (up to 20 dB for frequencies above 700 MHz) than a microstrip track of comparable length. Especially, packaging effects play a major role in this.

01 Jan 1998
TL;DR: In this paper, an inexpensive, simple, and sensitive workbench setup was developed to determine the transfer impedance ZT of shielded connectors, where the injection current was measured by an inductive sensor integrated in the setup.
Abstract: An inexpensive, simple, and sensitive workbench setup has been developed to determine the transfer impedance ZT of shielded connectors. The injection current is measured by an inductive sensor integrated in the setup. The induced voltage is determined by a spectrum/network analyzer. The overall sensitivity is 3 μΩ; the frequency range is up to 1 GHz. No special calibration samples are needed. As a demonstration the ZT is measured for both a coaxial tube with a small hole in the shield which provides a mutual inductance of 0.1 pH, and for some common connectors. Improvements in the design of the shield of a telecommunication connector are presented.

01 Jan 1998
TL;DR: In this paper, the authors describe some modelling techniques concerning the source, which allow the prediction of EM1 generated in SMPS with some topologies usually employed in space supply systems.
Abstract: Electromagnetic Compatibility (EMC) between the supply systems and the control and communications systems of a satellite is one of the key points to be checked when a supply system for such equipment is designed. Up to now, there is not much literature, neither simulation tools to predict the generation of disturbances in the power supply and its propagation through the whole system. This paper describes some modelling techniques concerning the source, which allow the prediction of EM1 generated in SMPS with some topologies usually employed in space supply systems. Concerning the propagation, the differential mode (DM) EMI produced by DC bus inductance and common mode (CM) capacitive coupling have been identified as the most significant mechanisms and a method for measuring both is proposed.

Patent
13 Nov 1998
TL;DR: In this article, a method and apparatus is provided for reducing or eliminating the amount of electromagnetic radiation being emitted from a system assembly comprising one or more subassemblies which comprise electrical circuits which generate electromagnetic radiation.
Abstract: A method and apparatus is provided for reducing or eliminating the amount of electromagnetic radiation being emitted from a system assembly comprising one or more subassemblies which comprise electrical circuits which generate electromagnetic radiation. The method and apparatus of the present invention also reduce or prevent electromagnetic radiation generated by sources outside of the system assembly from interfering with and adversely affecting the electrical circuits comprised in the subassemblies. To achieve these goals, the present invention provides an electromagnetic compatibility (EMC) solution which comprises a plurality of lossy elements, and/or elements comprised of a combination of lossy and conductive material, to reduce electromagnetic radiation. Thus, the conventional EMC solution, which utilizes conductive gaskets on system assemblies and subassemblies, and which requires adequate contact between parts in order to be effective, is replaced by the EMC solution of the present invention, which is more effective at higher frequencies and does not have stringent contact requirements.

Journal ArticleDOI
TL;DR: In this paper, the authors considered the problem of electromagnetic coupling through apertures of arbitrary shape in a perfectly conducting infinite screen of negligible thickness, and formulated an integral equation involving the equivalent magnetic current at the aperture and the electric current distribution on the wires, which is solved by the method of moments (MoM).
Abstract: Electromagnetic (EM) coupling through apertures of arbitrary shape in a perfectly conducting infinite screen of negligible thickness, is considered. In particular, general configurations that include the presence of wires are analyzed. These may be asymmetrically located on both sides of the aperture, with some element passing through the aperture. The problem is formulated in terms of an integral equation involving (as unknowns) the equivalent magnetic current at the aperture and the electric current distribution on the wires, which is solved by the method of moments (MoM). A set of measurements has been conducted to verify the accuracy of the technique.

Proceedings ArticleDOI
24 Aug 1998
TL;DR: In this article, the application of FDTD to the TC-9 challenge problems in EMC design is discussed, including initial results, the problem chosen for simulation, and the reasons for their choice.
Abstract: The integrity of a signal on an interconnect is affected by coupling due to other interconnects or the package, as well as discontinuities introduced by imperfect ground and power planes. Therefore, packaging and the specific layout of interconnects have a significant impact on the functional characteristics of a product. In order to prevent system problems, EMC/EMI concerns should be addressed at the design stage and not left as an afterthought. A full wave solution of the electromagnetic fields provide quantitative results for evaluation of signal integrity such as the current or voltage at specific points along the line. In addition, it also provides the electric and magnetic fields throughout. The structure that may lead to qualitative insights into the interactions between system components. Such insight may be an invaluable tool for solving EMC/EMI problems. The finite difference time domain (FDTD) technique is a full wave solver of the electromagnetic fields. This paper discusses the application of FDTD to the TC-9 challenge problems in EMC design including initial results, the problem chosen for simulation, and the reasons for our choice.

Proceedings ArticleDOI
24 Aug 1998
TL;DR: In this article, the interference characteristics between identical wireless LANs in the case of identical systems, systems with different technical parameters for modulation and demodulation, and using a Gaussian noise source as a disturbance source were investigated.
Abstract: Wireless LANs in the 2.4-GHz ISM-band create a new electromagnetic compatibility (EMC) problem. We investigated the interference characteristics between such wireless LANs in the case of identical systems, systems with different technical parameters for modulation and demodulation, and using a Gaussian noise source as a disturbance source. Experimental results show that higher throughput is obtained when adjacent wireless LANs use different systems, and that interference characteristics can be evaluated experimentally using a Gaussian noise source. Calculated BER characteristics for the interference agree with experimental measurements, indicating that this calculation method can be used for the design of the wireless LAN network to avoid interference. It is possible to construct an efficient wireless LAN network by combining different wireless LAN systems.

Proceedings ArticleDOI
15 Feb 1998
TL;DR: In this article, a comparison of different diodes used in boost power factor correctors (PFC) from the point of view of electromagnetic compatibility is presented, and the results show that the snap factor is important for the noise level and the reverse capacitance determines the ringing frequency and hence the noise peak.
Abstract: This paper presents a comparison of different diodes used in boost power factor correctors (PFC) from the point of view of electromagnetic compatibility. Diodes produced by various manufacturers, all with the same nominal recovery time, have been characterized and tested on a PFC circuit. Whereas the conducted emissions do not depend on the used diode, the radiated emissions are strongly influenced by the recovery behavior. In particular the snap factor is important for the noise level and the reverse capacitance determines the ringing frequency and hence the noise peak.

Proceedings ArticleDOI
24 Apr 1998
TL;DR: Through experience gained on a variety of micro controller-based products, the author has compiled a simple strategy for hardening microcontroller-based systems.
Abstract: As many design engineers have found, embedding microcontrollers into products provides extra features and functionality, but also introduces a new set of EMC problems, including susceptibility. Microcontroller-based equipment is particularly vulnerable to electrical transients such as electrostatic discharge (ESD), electrical fast transient bursts (EFT), high energy surges and supply dips, interruptions and variations. Hardware countermeasures should always be the first line of defence, to achieve any chance of immunity to transient phenomena. However, there are also defensive measures that may be applied in software. Through experience gained on a variety of microcontroller-based products, the author has compiled a simple strategy for hardening microcontroller-based systems.