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Focuses on the familiar problem of students' understanding of elementary electrical circuits from a much neglected point of view. Suggests that the patterning commonly found in students' ideas might have its roots in the cognitive processing with which students operate their mental models of d.c. electrical circuits. Studies Japanese 10-11 year olds living in the United Kingdom. (Contains 44 references.) (Author/YDS)

Human mobility in an urban area is complicated; the origins, destinations, and transportation modes of each person differ. The quantitative description of urban human mobility has recently attracted the attention of researchers, and it highly related to urban science problems. Herein, combined with physics inspiration, we introduce a revised electric circuit model (RECM) in which moving people are regarded as charged particles and analogical concepts of electromagnetism such as human conductivity and human potential enable us to capture the characteristics of urban human mobility. We introduce the unit system, ensure the uniqueness of the calculation result, and reduce the computation cost of the algorithm to 1/10,000 compared with the original ECM, making the model more universal and easier to use. We compared features including human conductivity and potential between different major cities in Japan to show our improvement of the universality and the application range of the model. Furthermore, based on inspiration of physics, we propose a route generation model (RGM) to simulate a human flow pattern that automatically determines suitable routes between a given origin and destination as a source and sink, respectively. These discoveries are expected to lead to new approaches to the solution of urban science problems. [ABSTRACT FROM AUTHOR]

Dry soil had a high electric resistance, and thus, electric fences are not always efficient in arid regions. When an animal standing on the ground touches the electric line, an electric circuit is formed and the animal gets shocked. Not only dry soil but also snow reduces the efficacy of electric fences. This is because liquid water is conductive, but solid snow is an insulator. However, the conductance of frozen soil is not studied enough. This study aims to investigate whether frozen soil reduces the effectiveness of electric fences and determines the electrical resistance of frozen soil. Four electric fences were installed on the forest edge in Yamanashi Prefecture, central Japan. From May 2021 to March 2022, two sensor cameras per fence were used to detect "probability of electrification" and "probability of intrusion into the fences." We treated from May to October 2021 and November 2021 to March 2022 as a non-frozen season (summer) and frozen season (winter), respectively. Results showed that in winter, the probability of electrification was decreased from 0.5 to 0.29 and the intrusion was increased from 0.03 to 0.07. When a pulsed current was applied, the electric conductance of frozen soil was reduced to 0.5% of that of the wet soil. Therefore, due to their reduced effectiveness in cold conditions, alternate grounding techniques for electric fences are required. For instance, the use of weed control sheet interwoven with stainless steel wire could be a practical solution. [ABSTRACT FROM AUTHOR]

Large capacitances are needed for low‐frequency active filters to process biomedical signals. The large capacitance can be implemented on a chip by an impedance scaling circuit. However, the characteristics of the circuit are affected by process variations. Then, we have proposed a digitally programmable impedance scaling circuit using electrical switches to compensate for the process variations. This paper describes a technique to reduce power consumption as compared with the conventional circuit. The proposed circuit is composed of a three‐stage current mirror circuit and electrical switches. To reduce the power consumption, the only signal current is amplified by current mirror circuits and bias current sources. The tuning range of the scaling factor of capacitance is from −35% to +28%, and the tuning accuracy is 1% using six switches. The validity of the proposed method is confirmed by simulations using HSPICE. The power consumption of the proposed circuit is reduced by 51% as compared with the conventional circuit. The proposed circuit is applied to a filter whose cutoff frequency is 100 Hz. From the tuning result, the tuning error is less than 1% for ±30% of ±3σ global variation and ± 3% of ±3σ local variation. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The National Metrology Institute of Japan (AIST, NMIJ) launched a project for the development of AC shunt standards. AC shunts allow the most precise measurement of current. A high-precision AC shunt is an important component of nonsinusoidal power standards. The AC shunt calibration system helps improve the uncertainty assessments of the national primary power standards. The calibration system design with uncertainties of up to 10 ppm requires a precise buffer amplifier which has uncertainties of up to 1 ppm in the frequency range from 10 Hz to 10 kHz, with other uncertainty components taken care of. The two buffer amplifiers dealt with in this paper were verified to have errors within 2 ppm and uncertainties within 1 ppm in in-phase and quadrature error in the frequency range from 10 Hz to 10 kHz. This also implies a possibility of reducing both in-phase and quadrature error at 10 kHz within 1 ppm, by taking advantage of both features. This paper describes the circuit design and evaluation results of two different buffer amplifiers. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(4): 24-31, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.21218 [ABSTRACT FROM AUTHOR]

This paper presents a new control circuit to create a high-performance noninverted buck-boost converter with dual ΔΣ modulations. Experimental load regulation, corresponding to load current steps of ±0.5 A, is within 45 mVpp, and the efficiency without a synchronized rectifier is 83% at an input voltage of 2.5 V and a load current of 0.8 A. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(2): 21-28, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.21115 [ABSTRACT FROM AUTHOR]

An ac shunt calibration system at the National Metrology Institute of Japan (NMIJ) has been developed. The uncertainties of the system were estimated 3.4 \mu\Omega/\Omega for in-phase and 8.6 \mu\rad for quadrature at 55 Hz/5 A. Meanwhile, the enhancement of the system is planned up to 10 kHz/10 A. For this goal, the accuracy and high-frequency performance of the buffer amplifier, which have the largest influence on the uncertainties, have been improved by developing a load effect reduction (LER) circuit. The LER circuit cancels out the effect of output impedance of the buffer amplifier. The effect of the circuit on the buffer amplifier allows the uncertainties of the ac shunt calibration system to be reduced into 2.6 \mu\Omega/\Omega and 8.2 \mu\rad at power frequencies. [ABSTRACT FROM AUTHOR]

The track circuit uses the rail as part of the circuit. The purposes of the track circuit are (1) to detect the train, (2) to transmit signals to the train, and (3) to detect rail breaks. There are two types of track circuit. One uses insulation joints at the end of the circuit, and the other is jointless. The insulation joint requires much effort to maintain and control. Furthermore, it is extremely expensive, and uses an insulation material, which is one of the weak points of the rail track. There are some methods for constructing a jointless track circuit, but they have several problems. The biggest one is that the border of the track circuits becomes fuzzy. Another is the interference of multiple track circuit signals. Nevertheless, jointless track circuits have high priority. First, they do not demand an insulation joint and impedance bonds. Second, they are very easy to divide. Jointless track circuits are used for sharp curves where it is impossible to install insulation joints on the Shinkansen line. Also, several conventional lines and private railways use this system. Furthermore, several European high-speed train systems also use jointless track circuits. Regarding Japan Railway, short-distance track circuits for level crossing control are jointless, but normal track circuits have insulation joints, because there is a legal restriction on track circuit border ambiguity. To solve this problem, the author worked out a simple jointless track circuit only with induction coils, whose border characteristics are excellent. Furthermore, it does not have a strong frequency characteristic and it can be applied to any frequency. In this paper, a new type of jointless track circuit is proposed and theoretically analyzed, and basic experiments are reported. © 1999 Scripta Technica, Electr Eng Jpn, 127(4): 64–76, 1999 [ABSTRACT FROM AUTHOR]

Mason's equivalent circuit is well known as a linear equivalent circuit for acoustic devices. By combining Mason's equivalent circuit with Smith's equivalent circuit of surface acoustic wave devices, it becomes a very effective tool for the physical interpretation of acoustic devices. If such equivalent circuit analysis can also be performed for the nonlinear problem, then comparatively simpler and accurate analysis can be obtained fur almost all types of nonlinear problems. In this paper, equations are formulated to analyze the equivalent circuit of nonlinear-type acoustic devices. At first, Mason's equivalent circuit is extended to the nonlinear region for the basic circuits of a thin bar of length-extensional vibration and a broad plate of thickness-extensional vibrations. Next, this equivalent circuit is used to analyze the thickness-extensional vibration of Z-cut LiNbO3 and second harmonic generation at the resonance point is clarified. Finally, these nonlinear equivalent circuits of length-extensional vibration are applied to determine the nonlinear constants of PZT ceramics end the nonlinear constants of the equivalent circuit are clarified. [ABSTRACT FROM AUTHOR]

This paper proposes a new construction method for 2-D IIR digital filters with all-pass subfilters as components. Recently, numerous studies have been made to construct digital filters by combining all-pass characteristics. This paper is based on the construction by a parallel connection of an all- pass subfilter and delay element, which can realize approximately the linear phase characteristic. First, the basic design for 1-D digital filters as well as its properties are described. Then the theory for the 1-D case is extended to the 2-D case, and a new construction method for 2-D digital filters with low-pass characteristics with circular symmetry is shown. The proposed method features the following. The phase characteristic is approximately linear in the passband. The filter can be realized with a smaller number of multipliers than in the traditional method. The coefficient sensitivity is low. [ABSTRACT FROM AUTHOR]

The dynamic characteristics of the capacitance of liquid-crystal display (LCD) pixel constituting the active matrix LCD device using amorphous thin film transistors (TFTs) have been analyzed; an electrically equivalent circuit model is proposed based on the obtained results. The model consists of nonlinear resistors and dynamic elements such as capacitors or inductors and can represent the voltage and time dependence of the capacitance value in the LCD pixel. The proposed model is incorporated into the circuit simulator SPICE as a built-in model. [ABSTRACT FROM AUTHOR]

In this paper, a low-profile filter using an open circular dual-mode dielectric resonator is proposed as a filter for a mobile communication base station. The basic configuration of the dielectric resonator consists of two dielectric disks with electrodes on both sides stacked in the axial direction; they sure installed in a shielded cavity. The doubly degenerate fundamental mode has an electric field parallel to the axial direction of the dielectric disks, and the resonator can be made low profile without significantly changing the resonant frequency. The equivalent circuit of the dual-mode resonator is given in terms of a ring-shaped transmission line with its electric length of 2π. The equivalent circuit of the multistage filter using this resonant circuit can be designed by the Chebyshev filter design method. A six-stage filter with the center frequency of 985 MHz and the passband width of 10 MHz was fabricated. The results agreed well with those of the simulation. The insertion loss at the center frequency is 1.3 dB, and the external dimensions are 158 × 54 × 23.5 mm. [ABSTRACT FROM AUTHOR]

In order to clarify the grounding conditions for protecting workers on a de-energized circuit from induction from a live circuit and to determine the required current capacity of the grounding conductor for a 1,000 kV double-circuit power transmission line, the phenomena caused by electromagnetic induction resulting from a live circuit are discussed. The electromagnetic induction current Ig flowing through the body of a worker and the electromagnetic induction current Ig0 flowing through the grounding conductor can be analyzed by dividing the various power line conditions into three main factors, and using electromagnetic induction current calculations for a power line of infinite length. The zone where Ig does not exceed 1 mA is within 1 km of the grounding point on the de-energized circuit owing to the grounding resistance (0.1&Omega) of the substations at the ends of the line and the difference in the phase configurations on the line when the current I1 of the live circuit is a constant 1 kA through the line. Similarly the value of Ig0 is determined by the grounding resistance of the substations at the ends of the line and the difference in the phase configurations on the line. Ig0 is approximately 10 A per 1 kA of I1.The currents Ig and Ig0 produced by electro-magnetic induction are additive, allowing Ig and Ig0 in the actual power line to be evaluated by summation. [ABSTRACT FROM AUTHOR]

Focuses on the grounding in the vicinity of the work site on 1000-kV power transmission lines in Japan. Magnitude of grounding current which determine the required size of the grounding conductor; Analysis of the effect of electrostatic induction from an in-service circuit to an out-of-service circuit; Stimulation of the interaction between two circuits of the double-circuit transmission line.

Development of a Circuit Breaker Condition Monitor - The most common primary electric power distribution voltage in Japan is 6 kV. Each feeder must have a circuit breaker (CB) for switching and protection. If the lubricating grease of a CB solidifies, its operation becomes slower, and this may eventually cause switching failure. This failure in turn causes expansion of the power outage area and slower power recovery. Grease solidification occurs more often when a CB has not functioned for a long period of time. Comparison between measured and expected (or normal) operation times is a very effective method of detecting grease solidification at an early stage and thus a very effective method of condition monitoring. [ABSTRACT FROM AUTHOR]

The article reports that Technical Committee on Dielectrics and Electrical Insulation in the Institute of Electrical Engineers of Japan (IEEJ) has established a series of investigation committees on ionic migration in printed wiring boards (PWB). The latest investigation committee is chaired by Y. Yamano and its members are preparing a draft of a book that will be published around the end of 2007. Topics to be tackled by the book include: the reliability of PWB; the characteristics of ionic migration; and methods of preventing ionic migration.

Information about several papers discussed at the meeting of IEC Working Groups (WGs) and Maintenance Team (MT) in the Japan Electrical Manufacturers' Association (JEMA) headquarters in Tokyo, Japan in April 16-20, 2007 is presented. Topics include the 10 IEC documents on coil insulation of rotating machines. It featured several machines including the IEC/TC112/WG3, IEC 60034-18-41/42, and PD inception voltage (PDIV)/PD extinction voltage (PDEV).

Reports on the development of a memory circuit that can count individual electrons at room temperature by a research team at NTT in Japan in 2004. Difference of the technique developed with the single-electronic devices that have been previously built; Creation of a nanowire FET with two gate controls; Action taken by team to be able to make the structure work at room temperature.

Presents a patent abstract for phase-locked loop circuit from Oki Electric Industry Co. Ltd. in Tokyo, Japan.