The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform

Takayoshi Kubono - One of the best experts on this subject based on the ideXlab platform.

  • Arc Duration and Rotational Frequency of Break Arcs Driven by Radial Magnet Field in a DC42V Resistive Circuit
    IEICE Transactions on Electronics, 2011
    Co-Authors: Naoya Takeshita, Junya Sekikawa, Takayoshi Kubono
    Abstract:

    Break arcs are rotated with the radial magnetic field formed by a magnet embedded in the fixed contact. They are generated in a DC42V Resistive Circuit. The Circuit current when the contacts are closed varies from 5A to 21A. The strength of a radial magnetic field for rotating break arcs changes. Arc duration is investigated. Then rotational frequency, arc length and Lorentz force when the periodic rotation of break arcs starts are analyzed to investigate the conditions required to rotate break arcs. The following results are obtained. The arc length L when the rotational motion of the break arc starts is almost constant at a constant magnetic flux density with an increase in Circuit current. The arc length L decreases with an increase in the magnetic flux density of the radial magnetic field. The rotational motion of break arcs starts when the arc length L reaches a certain value determined by magnetic flux density. Rotational frequency and Lorentz force increase linearly with an increase in Circuit current.

  • Break Arcs Driven by Transverse Magnetic Field in a DC48 V/6-24 A Resistive Circuit
    IEICE Transactions on Electronics, 2011
    Co-Authors: Toru Sugiura, Junya Sekikawa, Takayoshi Kubono
    Abstract:

    Silver electrical contacts are separated to generate break arcs in a DC48V/6-24A Resistive Circuit. The transverse magnetic field formed by a permanent magnet is applied to the break arcs. A series of experiments are carried out for two different experimental conditions. One condition is a constant contact separating speed while the magnetic flux density is changed to investigate the shortening effect of the arc duration. Another condition is a constant magnetic flux density while the contact separating speed is changed to investigate the changes in the arc duration and the contact gap when the break arc is extinguished. As a result, with constant separating speed, it is confirmed that the duration of break arcs is shortened by the transverse magnetic field and the break arcs are extinguished when the arc length reaches a certain value L. Under the condition of constant transverse magnetic field, (i) the arc duration is shortened by increasing the separation speed; (ii) the contact gap when the break arc is extinguished is almost constant when the separating speed v is sufficiently faster than 5mm/s.

  • Characteristics of Break Arcs Driven by Transverse Magnetic Field in a DC High-Voltage Resistive Circuit
    IEICE Transactions on Electronics, 2010
    Co-Authors: Tomohiro Atsumi, Junya Sekikawa, Takayoshi Kubono
    Abstract:

    Break arcs are generated between pure silver electrical contacts in a DC high-voltage Resistive Circuit. The break arc is driven by the external magnetic field of a permanent magnet from horizontal direction of contacts. Electrical contacts are separated at constant opening speed at 75 mm/s. The maximum supply voltage is 300 V. The maximum Circuit current when electrical contacts are closed is 20 A. The maximum output power of the supply is limited to 6.0 kW. The gap between the contacts and the magnet is defined as x. The gap is varied from 2.5 mm to 10.0 mm to change the magnetic flux density that affects the break arc. The break arc is observed with a high-speed camera. The effect of the magnetic field on the arc duration was examined. As a result, break arcs are successfully extinguished by the transverse magnetic field when the gap x is 2.5 mm. Then the length of the break arc just before lengthening of the break arc L and the Lorentz force that affects the break arc F are examined. The length L was almost constant for each gap x and independent of the Circuit current I and the Lorentz force F. The break arc is driven by the magnetic field when the arc length reached a certain length that was determined by the strength of the magnetic flux density.

  • Rotational Motion of Break Arcs Driven by Radial Magnetic Field in a DC Resistive Circuit
    IEICE Transactions on Electronics, 2009
    Co-Authors: Junya Sekikawa, Takayoshi Kubono
    Abstract:

    Break arcs are generated between silver electrical contacts in a DC 42V-10A Resistive Circuit. Break arcs are driven by the radial magnetic field. The magnetic field is formed between the electrical contacts with a permanent magnet embedded in the cathode. The arc motion is taken with a high-speed camera and contact surfaces are observed after break operations. Experimental results with the magnet are compared with those without the magnet to confirm the effect of the embedded magnet. For break operations with the magnet following results are shown. Break arcs are rotationally driven by the radial magnetic field in the direction according to Lorentz force. The shortening effect of the arc duration is confirmed. The traces of the arc spots on the contact surfaces are ringshaped, wide and uniform. This result shows the prevention effect of local erosion of electrical contacts. The rotational frequency of the break arc depends on the Lorentz force with the radial magnetic field.

  • Time-Resolved Spectroscopic Temperature Measurement of Break Arcs in a D.C.42 V Resistive Circuit
    IEICE Transactions on Electronics, 2008
    Co-Authors: Junya Sekikawa, Naoki Moriyama, Takayoshi Kubono
    Abstract:

    In a D.C.42 V-10A Resistive Circuit, break arcs are generated between electrical contact pairs. The materials of the contact pairs are Ag, Ag/C 2wt%, Ag/SnO 2 12wt%, and Ag/ZnO 12wt%. The arc spectral intensities are measured by a time-resolved spectroscopic temperature measurement system. The arc temperature is calculated from the spectral intensities by using the method of relative intensities of two spectra. The experimental results are as follows. The arc temperature gradually decreases with increase of the gap of electrical contacts. The ranges of arc temperature for Ag, Ag/C 2wt%, Ag/SnO 2 12wt%, and Ag/ZnO 12wt% contacts pairs are 4500-11000 K, 4000-6000 K, 4000-7000 K, and 4000-11000 K, respectively.

Junya Sekikawa - One of the best experts on this subject based on the ideXlab platform.

  • Arc Duration and Rotational Frequency of Break Arcs Driven by Radial Magnet Field in a DC42V Resistive Circuit
    IEICE Transactions on Electronics, 2011
    Co-Authors: Naoya Takeshita, Junya Sekikawa, Takayoshi Kubono
    Abstract:

    Break arcs are rotated with the radial magnetic field formed by a magnet embedded in the fixed contact. They are generated in a DC42V Resistive Circuit. The Circuit current when the contacts are closed varies from 5A to 21A. The strength of a radial magnetic field for rotating break arcs changes. Arc duration is investigated. Then rotational frequency, arc length and Lorentz force when the periodic rotation of break arcs starts are analyzed to investigate the conditions required to rotate break arcs. The following results are obtained. The arc length L when the rotational motion of the break arc starts is almost constant at a constant magnetic flux density with an increase in Circuit current. The arc length L decreases with an increase in the magnetic flux density of the radial magnetic field. The rotational motion of break arcs starts when the arc length L reaches a certain value determined by magnetic flux density. Rotational frequency and Lorentz force increase linearly with an increase in Circuit current.

  • Break Arcs Driven by Transverse Magnetic Field in a DC48 V/6-24 A Resistive Circuit
    IEICE Transactions on Electronics, 2011
    Co-Authors: Toru Sugiura, Junya Sekikawa, Takayoshi Kubono
    Abstract:

    Silver electrical contacts are separated to generate break arcs in a DC48V/6-24A Resistive Circuit. The transverse magnetic field formed by a permanent magnet is applied to the break arcs. A series of experiments are carried out for two different experimental conditions. One condition is a constant contact separating speed while the magnetic flux density is changed to investigate the shortening effect of the arc duration. Another condition is a constant magnetic flux density while the contact separating speed is changed to investigate the changes in the arc duration and the contact gap when the break arc is extinguished. As a result, with constant separating speed, it is confirmed that the duration of break arcs is shortened by the transverse magnetic field and the break arcs are extinguished when the arc length reaches a certain value L. Under the condition of constant transverse magnetic field, (i) the arc duration is shortened by increasing the separation speed; (ii) the contact gap when the break arc is extinguished is almost constant when the separating speed v is sufficiently faster than 5mm/s.

  • Characteristics of Break Arcs Driven by Transverse Magnetic Field in a DC High-Voltage Resistive Circuit
    IEICE Transactions on Electronics, 2010
    Co-Authors: Tomohiro Atsumi, Junya Sekikawa, Takayoshi Kubono
    Abstract:

    Break arcs are generated between pure silver electrical contacts in a DC high-voltage Resistive Circuit. The break arc is driven by the external magnetic field of a permanent magnet from horizontal direction of contacts. Electrical contacts are separated at constant opening speed at 75 mm/s. The maximum supply voltage is 300 V. The maximum Circuit current when electrical contacts are closed is 20 A. The maximum output power of the supply is limited to 6.0 kW. The gap between the contacts and the magnet is defined as x. The gap is varied from 2.5 mm to 10.0 mm to change the magnetic flux density that affects the break arc. The break arc is observed with a high-speed camera. The effect of the magnetic field on the arc duration was examined. As a result, break arcs are successfully extinguished by the transverse magnetic field when the gap x is 2.5 mm. Then the length of the break arc just before lengthening of the break arc L and the Lorentz force that affects the break arc F are examined. The length L was almost constant for each gap x and independent of the Circuit current I and the Lorentz force F. The break arc is driven by the magnetic field when the arc length reached a certain length that was determined by the strength of the magnetic flux density.

  • Rotational Motion of Break Arcs Driven by Radial Magnetic Field in a DC Resistive Circuit
    IEICE Transactions on Electronics, 2009
    Co-Authors: Junya Sekikawa, Takayoshi Kubono
    Abstract:

    Break arcs are generated between silver electrical contacts in a DC 42V-10A Resistive Circuit. Break arcs are driven by the radial magnetic field. The magnetic field is formed between the electrical contacts with a permanent magnet embedded in the cathode. The arc motion is taken with a high-speed camera and contact surfaces are observed after break operations. Experimental results with the magnet are compared with those without the magnet to confirm the effect of the embedded magnet. For break operations with the magnet following results are shown. Break arcs are rotationally driven by the radial magnetic field in the direction according to Lorentz force. The shortening effect of the arc duration is confirmed. The traces of the arc spots on the contact surfaces are ringshaped, wide and uniform. This result shows the prevention effect of local erosion of electrical contacts. The rotational frequency of the break arc depends on the Lorentz force with the radial magnetic field.

  • Time-Resolved Spectroscopic Temperature Measurement of Break Arcs in a D.C.42 V Resistive Circuit
    IEICE Transactions on Electronics, 2008
    Co-Authors: Junya Sekikawa, Naoki Moriyama, Takayoshi Kubono
    Abstract:

    In a D.C.42 V-10A Resistive Circuit, break arcs are generated between electrical contact pairs. The materials of the contact pairs are Ag, Ag/C 2wt%, Ag/SnO 2 12wt%, and Ag/ZnO 12wt%. The arc spectral intensities are measured by a time-resolved spectroscopic temperature measurement system. The arc temperature is calculated from the spectral intensities by using the method of relative intensities of two spectra. The experimental results are as follows. The arc temperature gradually decreases with increase of the gap of electrical contacts. The ranges of arc temperature for Ag, Ag/C 2wt%, Ag/SnO 2 12wt%, and Ag/ZnO 12wt% contacts pairs are 4500-11000 K, 4000-6000 K, 4000-7000 K, and 4000-11000 K, respectively.

Alberto Poveda - One of the best experts on this subject based on the ideXlab platform.

  • Digitally programmable MOS Resistive Circuit
    Electronics Letters, 2002
    Co-Authors: Eduard Alarcon, Herminio Martinez, E Vidal, Alberto Poveda
    Abstract:

    A mixed-signal cell is presented which operates as a digitally-controlled differential resistor and is suited to programmable continuous-time MOSFET-C filter applications. The cell is based on a digitally-controlled extension of the MOS Resistive Circuit (MRC) cell, in which digital tunability is obtained by embedding in the MRC transistors both the triode-region and switch functionalities, providing a compact implementation that preserves Circuit performance. Post-layout simulation results for a 3-bit prototype in 0.8 /spl mu/m CMOS technology validate the feasibility of the proposed cell and its application to a digitally-tunable continuous-time MOSFET-C filter.

  • Design and implementation of an MRC-C TQE filter with on-chip automatic tuning
    Proceedings of the 44th IEEE 2001 Midwest Symposium on Circuits and Systems. MWSCAS 2001 (Cat. No.01CH37257), 2001
    Co-Authors: Herminio Martinez, E Vidal, Eduard Alarcon, Alberto Poveda
    Abstract:

    This work describes the design and implementation of the tuning loops (both central frequency and quality factor control loops) for a bandpass continuous-time fully-balanced filter based on a modification of the Transimpedance Q-Enhancement (TQE) structure, intended for audio-band applications. The Circuit has been designed and fabricated in a CMOS 0.8 /spl mu/m technology, and MRC (MOS Resistive Circuit) cells have been used to implement electronically tunable active resistors. Both post-layout transistor-level simulation results and experimental results validate the functionality of the tuning system.

  • Nonlinear analytical model of the MRC (MOS Resistive Circuit)
    42nd Midwest Symposium on Circuits and Systems (Cat. No.99CH36356), 1
    Co-Authors: E Vidal, Herminio Martinez, Eduard Alarcon, Alberto Poveda
    Abstract:

    We analyze the significant departures between the predicted behavior and the actual performance of MOS Resistive Circuit cells (MRC) due to mobility degradation. These effects are mainly a difference in the value of the resistance implemented, and a nonlinear behavior. A model including these effects is proposed and shown to work through an example.

  • ISCAS - Complete nonlinear model for the MRC (MOS Resistive Circuit)
    2000 IEEE International Symposium on Circuits and Systems. Emerging Technologies for the 21st Century. Proceedings (IEEE Cat No.00CH36353), 1
    Co-Authors: E Vidal, Herminio Martinez, Eduard Alarcon, Sonia Porta, Alberto Poveda
    Abstract:

    The most significant sources of nonlinearity in the MOS Resistive Circuit behaviour are identified and deeply analysed in this contribution. Their influence on the MRC performance and, therefore, in the Circuits containing such structure is evidenced through some examples and evaluated. Some reasonable hints about the way to minimise their undesired effects are provided.

  • D-MRC: digitally programmable MOS Resistive Circuit
    Proceedings of the 44th IEEE 2001 Midwest Symposium on Circuits and Systems. MWSCAS 2001 (Cat. No.01CH37257), 1
    Co-Authors: Eduard Alarcon, Herminio Martinez, E Vidal, Jordi Madrenas, Alberto Poveda
    Abstract:

    This paper presents the D-MRC Circuit, a mixed-signal cell which operates as a digitally-controlled differential resistor, and that is suited to programmable continuous-time MOSFET-C filter applications. The cell is based on a digitally-controlled extension of the MRC (MOS Resistive Circuit) cell, in which digital tunability is obtained by embedding in the same MRC transistors both the triode-region and switch functions, providing a compact implementation that preserves Circuit performance. This cell is of interest for static and dynamic reconfigurability of mixed-signal Circuits, as required in multistandard wireless CMOS receivers. The proposed cell has been designed down to the layout level for a particular prototype with 3-bit digital controllability in 0.8 /spl mu/m CMOS technology. Post-layout simulation results validate the functionality of the proposed cell and its application to a digitally-tunable continuous-time MOSFET-C filter.

M. Hasler - One of the best experts on this subject based on the ideXlab platform.

  • Convexity of Resistive Circuit Characteristics
    1997
    Co-Authors: C. Wang, M. Hasler
    Abstract:

    We give topological criteria for the convexity and the concavity of a current or a voltage in a Resistive Circuit, as a function of a source voltage or current, when the nonlinear resistor characteristics are all either convex or concave. When the criteria are satisfied, all Circuits with the same structure will have a convex, or all will have a concave transfer characteristic. The application of the criterion to ladder Circuits leads to explicit and easily verifyable conditions.

  • Algorithms for the qualitative analysis of nonlinear Resistive Circuits
    IEEE International Symposium on Circuits and Systems, 1
    Co-Authors: M. Fosseprez, M. Hasler
    Abstract:

    An algorithm that decides whether a given Resistive Circuit has a pair of conjugate trees and/or a nontrivial uniform partial orientation of the resistors is presented. The algorithm in the case of conjugate trees is of polynomial order in the number of branches, whereas for the uniform partial orientation problem it is potentially of exponential complexity. However, the constraint-propagation method is capable of reducing considerably the computational burden for the orientation problem. The two problems are central to the qualitative analysis of nonreciprocal Circuits. >

  • Resistive Circuits with several solutions
    1988. IEEE International Symposium on Circuits and Systems, 1
    Co-Authors: M. Fosseprez, M. Hasler
    Abstract:

    Necessary and sufficient conditions are given under which a Resistive Circuit may have several, but finitely many solutions. Whether it actually has several solutions depends on the values of the sources and linear resistors as well as on the characteristics of the nonlinear resistors. Such Circuits are required for static memory applications of all kinds, including associative memories realized by neural networks. These criteria are given in terms of linear Circuits and Circuit topology. In addition, the minimal memory Circuits are characterized. They constitute the building blocks for more complicated memory Circuits. >

Zhimiao Yan - One of the best experts on this subject based on the ideXlab platform.

  • Nonlinear analysis of galloping piezoelectric energy harvesters with inductive-Resistive Circuits for boundaries of analytical solutions
    Communications in Nonlinear Science and Numerical Simulation, 2018
    Co-Authors: Zhimiao Yan, Ting Tan, Weipeng Sun, Wenhu Huang
    Abstract:

    Abstract For nonlinear characterization of the galloping piezoelectric energy harvester with the inductive-Resistive Circuit, the electromechanical coupled distributed parameter model is concisely retrospected. A general electromechanical decoupled model is proposed for the series and parallel Circuits with different algebraic expressions of the electrical damping and modified frequency. The electrical damping corresponding to Hopf bifurcation (EDHB) is derived and noticed to be linearly and positively varied with the wind speed. Galloping occurs when the electrical damping is smaller than EDHB. To analyze the effects of the electrical Circuits on Hopf bifurcation, the inductance corresponding to Hopf bifurcation (IHB) is proposed as a function of the load resistance and EDHB. The stable and galloping regions of the inductance and modified frequency varied with the wind speed are determined and found to be strongly dependent on the load resistance. Hopf bifurcation for the small load resistance of the series connection is similar as that for the large load resistance of the parallel case, and vice versa. The time history, phase portrait and power spectrum are introduced to show the differences between the results obtained with the small and large initial conditions. It is found that the large initial condition corresponds to the large electrical damping and the small initial condition relates to the small electrical damping. This is expected to be the reason that the large electrical damping is more difficult to be excited. Different from our common concept, the tip displacement with the small initial condition is larger than that with the large initial condition in some situations. With the galloping region determined by the presented nonlinear analyses, the analytical solutions agree well with the numerical results using the small and large initial conditions.

  • Optimization study on inductive-Resistive Circuit for broadband piezoelectric energy harvesters
    AIP Advances, 2017
    Co-Authors: Ting Tan, Zhimiao Yan
    Abstract:

    The performance of cantilever-beam piezoelectric energy harvester is usually analyzed with pure Resistive Circuit. The optimal performance of such a vibration-based energy harvesting system is limited by narrow bandwidth around its modified natural frequency. For broadband piezoelectric energy harvesting, series and parallel inductive-Resistive Circuits are introduced. The electromechanical coupled distributed parameter models for such systems under harmonic base excitations are decoupled with modified natural frequency and electrical damping to consider the coupling effect. Analytical solutions of the harvested power and tip displacement for the electromechanical decoupled model are confirmed with numerical solutions for the coupled model. The optimal performance of piezoelectric energy harvesting with inductive-Resistive Circuits is revealed theoretically as constant maximal power at any excitation frequency. This is achieved by the scenarios of matching the modified natural frequency with the excitatio...