DC Electrical Circuits Research Articles

Development of New Electrons Sources for coil-EEFL Tube

After the critical study on the established FL tubes, it has found a formation of the new internal DC electric power generator in the Ar gas space between the needle cathode and anode. The internal DC electric power generator, which completely isolates from the external DC electric circuit by the electron flow, forms with the volumes of the glow light in front of the needle electrodes that are covered with the layer of the frit glass. The lights are generated by the moving electrons between the cathode and anode of the internal DC electric power generator. The results lead us to the development of the prototype of the coil-EEFL tube that has zero power consumption of the external DC driving circuit.

Effect of Conceptual Change Oriented Instruction on Students’ Conceptual Understanding and Decreasing Their Misconceptions in DC Electric Circuits

The purpose of this study was twofold: first to investigate the effect of conceptual change oriented instruction accompanied by concept cartoon worksheet with simulation on students’ conceptual understanding and second to remedy their misconceptions of direct current electric circuits. Participants were 139 pre-service science teachers from four intact classes. A quasi-experimental design was used in the study. The experimental group studied the concept with the application of concept cartoon worksheet and simulation, and the control group studied it with traditional instruction. Students’ conceptual understanding and misconceptions were measured by a tree-tired misconception test. It was administered as pre-and-posttest. There was no significant difference between the means of pre-test scores of experimental and control groups. The main effect of treatment on post-test scores was examined via ANCOVA with pre-test scores used as covariate. The frequency of each misconception was calculated for both groups, from pre to post-tests regarding all tiers of items. The analysis yielded a significant treatment effect on students’ post-test performances. The findings indicated that the conceptual change oriented instruction accompanied by concept cartoon worksheet and simulation is likely to be effective for conceptual understanding and decreasing most of students’ misconceptions in direct current electric circuits.

Implementation of nanoscale double-gate CMOS circuits using compact advanced transport models

In this paper we present the results of the implementation of a nanoscale double-gate (DG) MOSFET compact model, which includes hydrodynamic transport model, in Verilog-A in order to carry out circuit simulation. The model in Verilog-A is used with the SMASH circuit simulator for the analysis of the DC and transient behavior electrical CMOS circuits. Template devices representative for a downscaled symmetric double-gate MOSFET was used to validate the models for n-channel and p-channel. A CMOS inverter and a ring oscillator have been analyzed. Comparison of its performance between the drift-diffusion (DD) and hydrodynamic transport model within the practical range of bias voltages has been highlighted.

Improvement of large scale solar installation model for ground current analysis

Application of a simplified PV model to large-scale PV installations neglects the current distortion, potential rise and losses in the system as consequence of the capacitive coupling inside the dc electric circuit. These capacitive couplings represent a leakage impedance loop for the capacitive currents imposed by the high frequency switching performance of power converters. This paper proposes a suitable method to reproduce these harmonic currents injected not only into the grid, but also into the dc circuit of the PV installation. The capacitive coupling proposed of PV modules with ground is modeled as a parallel resistance and capacitor arrangement which leads to an accurate approximation to the real operation response of the PV installation. Results obtained are compared with those of simplified models of PV installations used in literature. An experimental validation of the proposed model was performed with field measurements obtained from an existing 1 MW PV installation. Simulation results are presented together with solutions based on the proposed model to minimize the capacitive ground current in this PV installation for meeting typical power quality regulations concerning to the harmonic distortion and safety conditions and to optimize the efficiency of the installation.

A Corpus-based Evaluation of a Domain-specific Text to Knowledge Mapping Prototype

The aim of this paper is to evaluate a Text to Knowledge Mapping (TKM) Prototype. The prototype is domain-specific, the purpose of which is to map instructional text onto a knowledge domain. The context of the knowledge domain is DC electrical circuit. During development, the prototype has been tested with a limited data set from the domain. The prototype reached a stage where it needs to be evaluated with a representative linguistic data set called corpus. A corpus is a collection of text drawn from typical sources which can be used as a test data set to evaluate NLP systems. As there is no available corpus for the domain, we developed and annotated a representative corpus. The evaluation of the prototype considers two of its major components- lexical components and knowledge model. Evaluation on lexical components enriches the lexical resources of the prototype like vocabulary and grammar structures. This leads the prototype to parse a reasonable amount of sentences in the corpus. While dealing with the lexicon was straight forward, the identification and extraction of appropriate semantic relations was much more involved. It was necessary, therefore, to manually develop a conceptual structure for the domain to formulate a domain-specific framework of semantic relations. The framework of semantic relationsthat has resulted from this study consisted of 55 relations, out of which 42 have inverse relations. We also conducted rhetorical analysis on the corpus to prove its representativeness in conveying semantic. Finally, we conducted a topical and discourse analysis on the corpus to analyze the coverage of discourse by the prototype.

A study on the impact of real, virtual and comprehensive experimenting on students’ conceptual understanding of DC electric circuits and their skills in undergraduate electricity laboratory

The purpose of this study is to investigate the comparative value of performing electricity laboratory by physical, virtual and comprehensive (combination of virtual and physical) methods with respect to changes in students ‘conceptual understanding of DC electric circuits and their skills. To achieve these, a pre–post comparison test (DIRECT V1.2) and final skill test that include coordinated tasks of assembling a real circuit and describing how it worked, were used that involved 100 undergraduate students. At the end of the study by means of statistical tests, we observed considerable changes in comprehensive group's learning and virtual group's skill in comparison with the other groups.

Regularities and mechanism of triboelectric processes in metal-polymer tribosystems

The results of study of the circuit configuration of an external source of electric current on the wear rate of polytetrafuorehylene-based polymeric composite materials with various concentrations of superdispersed filler are considered. The mechanisms of tribo-EMF generation and appearance of the friction transfer film during friction of polymeric composites with a steel counterbody in a DC electric circuit are described. It is shown that the configuration of the metal-polymeric friction unit in the electric circuit affects its wear resistance.

Early failure signatures of 1310 nm laser modules using electrical, optical and spectral measurements

In this paper, we propose a methodology to discriminate electro-optical failure signatures related to an optical alignment drift in the laser module in comparison of those related to the gradual change of electro-optical parameters of the laser diode. A specific test bench with temperature dependence has been developed to monitor P( I), I( V) and L( λ) of 15 DCBH InGaAsP/InP 1310-nm Fabry-Perot laser modules and has allowed to extract three main failure signatures after 300 thermal cycles. A study of experimental I( V) curves from reference laser modules has resulted in the development of a DC electrical circuit with a non-linear element tunnel diode D tunnel contributing to a better understanding of current distribution parallel paths inside the laser diode. After accelerated ageing tests, two signatures are related to an gradual change of both electrical and optical parameters conducting to identify failure mechanisms in the laser diode and discrimination of failures zone was improved by a reverse bias I( V) measurement. The third signature has shown an optical gradual change without any modification of the threshold current or ideality factor. We also demonstrate the strong interest of L( λ) measurements complementary to I( V) and P( I) characteristics.

Photoconductive films of poly- N-vinylindole-based blends for high-voltage photorefractive electrooptic cells

In the frame of our research on the electrooptic behavior of poly- N-vinylindole (PVI) and a series of its methyl derivatives, we have measured the photoconductivity of poly-2,3-dimethyl- N-vinylindole (PV2,3DMI) at room temperature. The measurements have been accomplished on 100 μm-thick films obtained by squeezing the polymer between two ITO sheets at about 130 °C. The electrooptic cell was introduced in a dc electric circuit, and a voltage up to 15,000 V could be applied between the ITO sheets while irradiating at λ=685 nm and at a power of the order of 10 mW with a laser diode. Very special care had to be taken in order to allow the use of such high voltages, like for instance a thermal treatment at about 150 °C of the sample held under vacuum during a few minutes. The measured photoconductivity of PV2,3DMI was higher than that of PVI but lower than that of poly- N-vinylcarbazole (PVK). The result obtained for PV2,3DMI confirms the anticipated positive effect of the two methyl groups in lowering the ionization potential of the N-alkylindole. PV2,3DMI has shown a good compatibility with a NLO molecule, giving very transparent and stable films for photorefractivity tests. A two-beam coupling (2BC) electrooptic circuit for photorefractivity measurements has been built and tested with PVK blends.

Worst-case tolerance analysis of linear DC and AC electric circuits

This paper addresses the problem of worst-case tolerance analysis of steady states in linear DC and AC electric circuits. The statement of the problem considered is in the form of linear algebraic equations whose elements are, in the general case, nonlinear functions of a given set of independent interval parameters. Three kinds of solutions are considered: 1) outer solution; 2) inner solution and 3) exact solution. A direct method for computing an outer solution and an iterative method for finding an inner solution are suggested. The inner and outer solutions thus found provide a tight two-sided bound on the exact solution of the tolerance problem investigated. The exact solution can be determined if certain monotonicity conditions are fulfilled. The verification of the conditions involves solving several associated outer solution problems. The computational efficiency of the methods suggested is demonstrated by a numerical example.

Xylem ingestion by winged aphids

AbstractWhen aphids and their host plant are incorporated in a DC electrical circuit, phloem and xylem ingestion register as separate waveforms of the electrical penetration graph (EPG) signal. Aphids are primarily phloem feeders; xylem ingestion is seldom reported but can be induced experimentally by fasting the insects in desiccating conditions. In experiments with the black bean aphid, Aphis fabae Scop., young winged (alate) and unwinged (apterous) virginoparous adults were collected from their natal host plants (broad bean, Vicia faba L.) and allowed 3‐h continuous EPG‐recorded access to V. faba seedlings. Several aphids (47% of both morphs) showed ingestion from phloem sieve elements. Alate aphids also showed frequent xylem ingestion (60% of individuals), but no apterous aphids exhibited this activity. The EPG technique involves attachment of a fine gold wire electrode to each insect, a process that may affect normal behaviour at the plant surface. However, when the technique was modified to monitor the stylet activities of freely‐settled aphids, high levels of xylem ingestion by alates were also recorded. The results suggest that the developmental physiology of winged aphids somehow predisposes them to xylem ingestion, possibly as a result of dehydration during the teneral period. Alate aphids may reduce their weight by fasting before take‐off, giving aerodynamic benefits, but making rehydration, via xylem uptake, a priority following plant contact.

A testing system for diagnosing misconceptions in DC electric circuits

A testing-based diagnosing system is implemented. The system has a problem library that collects some suitable problems and associated answers. The answers of each problem are related to misconceptions. Problem selector in the system provides some problems to test student. Based on the student's answers, the diagnoser in the system will discriminate the student's misconceptions. The problem selector and the diagnoser are implemented with matrix operations. For evaluating the performance of the system, the topic of basic DC electricity is used as the subject domain. There are nine types of misconceptions found in basic electricity. Based on the experimental results, the system has the satisfactory diagnosis.

SPICE applications in education: insulator strings of overhead transmission lines

SPICE is a general-purpose simulation program for the analysis of DC or AC electrical circuits. In the present paper, the usefulness of the SPICE circuit analysis program is demonstrated as an educational tool in overhead transmission line insulator analysis. Two circuits are presented. One is a string of suspension insulators and the other is the grading ring. Both circuits are analyzed for the variation of the voltage distribution on the insulators against time.

ジャンプフラッシング放電加工の等価モデル（第２報） パルスデューティ比の影響

This study aims to represent the characteristics of the jump-flushing EDM by a simple mathematical model in order to realize suitable selections of jump parameters through computer simulations.In the previous report, we proposed a basic model from a consideration of similarity between the increasing process of machining products in the working gap and the charging process of a capacitance in the DC electrical circuit. As a result, that model showed validities to represent a change in machining characteristics and jump parameters with progression of machining.In the present report, we propose an expanded model in which influences of duty factor of working pulses are taken into consideration. Computer simulations based on the new model showed that suitable jump parameters and rest time of working pulse are able to be estimated. Further expansion of the model will be possible by considering influences of peak current or pulse duration in the similar way of the duty factor.

ジャンプフラッシング放電加工の等価モデル （第１報） 電気回路によるモデル表現

In the diesinking EDM, the jump flushing is generally known to be useful to clean up the working gap. However, it is very difficult to adjust the jump parameters efficiently such as an amplitude and an execution timing of the jump motion with progress of machining. Because, in this process, optimal values of such parameters change widely with progress of machining and to adjust them an extensive expert knowledge about the jump control is required. Therefore, if a numerical equivalent model of the jump flushing EDM can be framed, it will be very useful for adaptive adjustment of the jump parameters.This report describes a newly proposed equivalent model of the jump flushing EDM represented by an electrical way. Increasing process of the machining products in the working gap is converted to the charging process of a condenser in a DC electric circuit. Efficient jump timing is able to be computed from the rising time of the terminal voltage of the condenser to a threshold value which corresponds to critical density of the machining products for the safety sparking.Results of computer simulations based on the proposed model show that the machining characteristics of the jump flushing EDM could be reproduced sufficiently except for the very early stage of machining. Besides, it was found that approximate optimal values of the jump parameters could be computed easily.

A Genetic Epistemological Analysis of Data on Children's Ideas about DC Electrical Circuits

Abstract This study reports a new analysis of data on children's ideas about DC electrical circuits. The analysis is theoretically informed by Piagetian stage theory of genetic epistemology. The analysis uses survey data reported by Shayer & Adey to predict the proportion of pupils in any given age cohort that will be able to successfully tackle questions on simple DC circuits. The quantitative predictions are tested against research data published by other workers. The success of this enterprise strengthens the Piagetian genetic epistemological claims to explanatory power of children's cognitive processes and thereby to offer a framework for the structuring of learning experiences.

The SPICE 3 programming language and its application to power system analysis

The authors describe the use of the SPICE 3 programming language for power system fault analysis. SPICE 3 is a general-purpose simulation program for analysis of DC or AC electrical circuits. One of the additional features of this language as compared to its previous version is its ability to model the operations of a switch. It is concluded that this makes SPICE 3 quite suitable for transient analysis of electrical circuits. The versatility and capability of this language are demonstrated by two simple example problems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Electric Circuits and Machines

The instructor's manual to a user-friendly introduction to DC and AC electrical theory, circuits and equipment; the only prerequisite is algebra and a basic knowledge of trigonometry. The main text reflects changes in industry due to increasing computerization of electrical equipment. Modern solid-state components are also covered in appropriate sections throughout the book, particularly in the area of industrial controls. This material is only available to lecturers.