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Electrical impedance

About: Electrical impedance is a research topic. Over the lifetime, 36015 publications have been published within this topic receiving 371891 citations. The topic is also known as: electrical impedance & complex impedance.


Papers
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Journal ArticleDOI
TL;DR: It is concluded that FEM models of electrodes can be used to improve the performance of an electrical impedance tomography reconstruction algorithm.
Abstract: In electrical impedance tomography (EIT), the measured voltages are sensitive to electrode-skin contact impedance because the contact impedance and the current density through it are both high. Large electrodes were used to provide a more uniform current distribution and reduce the contact impedance. A large electrode differs from a point electrode in that it has shunting and edge effects that cannot be modeled by a single resistor. The finite-element method (FEM) was used to study the electric field distributions underneath an electrode, and three models were developed: a FEM model, a simplified FEM model, and a weighted load model. The FEM models considered both shunting and edge effects and closely matched the experimental measurements. It is concluded that FEM models of electrodes can be used to improve the performance of an electrical impedance tomography reconstruction algorithm. >

103 citations

Journal ArticleDOI
TL;DR: In this paper, a method to determine the equivalent circuit of a semiconductor/electrolyte/counterelectrode cell is presented, where the analog of the phenomenon leading to frequency dependent behavior has been taken to be a resistor in series with a capacitor.
Abstract: A method to determine the equivalent circuit of a semiconductor/electrolyte/counterelectrode cell is presented. The electrical analog of the phenomenon leading to frequency dependent behavior has been taken to be a resistor in series with a capacitor. The case where a large number of RC elements are present has been determined in the following way. The values of the capacitances and time constants of these elements have been assumed to be distributed exponentially. For this distribution it follows that the equivalent circuit can be represented as a frequency dependent resistor in parallel with a frequency dependent capacitor. Expressions for the frequency dependent resistance and capacitance have been derived. The impedance and admittance responses of a large number of circuits have been simulated. The circuit which best represented an n-Fe/sub 2/O/sub 3/ (1% TiO/sub 2/)/1M NaOH/Pt cell was determined by comparing the simulated responses with the measured responses. 18 refs.

102 citations

Journal ArticleDOI
TL;DR: In this article, the authors developed impedance models for the rectifier ac system and the inverter ac system for a VSC-HVDC system and examined the resonance stability using Nyquist stability criterion and impedance frequency responses.
Abstract: Resonances can limit power transfer in a voltage-source converter-high voltage dc (VSC-HVDC) system. The objective of this paper is to develop impedance models for the rectifier ac system and the inverter ac system for a VSC-HVDC system. Resonance stability will be examined using Nyquist stability criterion and impedance frequency responses. The impedance models consider the outer control loop and the inner current control loops of VSCs. Impacting factors are then examined. Stability analysis demonstrates that the feedforward filter, line length, and power transfer level have a significant impact on resonances. Time-domain simulation results obtained by Matlab SimPowerSystems are used to validate the analysis.

102 citations

Journal ArticleDOI
TL;DR: In this paper, an offset parallel-coupled strip configuration is described, in which the mechanical parameters are strip width, strip offset, and ratio of strip spacing to ground-plane spacing.
Abstract: An offset parallel-coupled strip configuration is described, in which the mechanical parameters are strip width, strip offset, and ratio of strip spacing to ground-plane spacing. The electrical parameters are dielectric constant, characteristic impedance, even and odd mode impedance. The configuration is analyzed by conformal rnapping techniques. Explicit design equations are derived in which the mechanical parameters are expressed in terms of the electrical parameters. Illustrative results are presented, and the limitations on coupling strength, characteristic impedance, and strip configuration are discussed.

102 citations

Journal ArticleDOI
TL;DR: In this article, a two current probes approach is used to determine common-mode and differential-mode (DM) noise source impedances of a low-power switched mode power supply (SMPS) using a two-current probes approach.
Abstract: A novel approach to determine common-mode (CM) and differential-mode (DM) noise source impedances of a low-power switched mode power supply (SMPS) has been developed using a two current probes approach. The proposed approach allows measurement of noise source impedance of a SMPS without interrupting its normal operation. With proper setup calibration, the proposed approach can derive an equivalent circuit model, consisting of resistive and reactive components, to represent the noise source impedance with reasonable accuracy. Once the equivalent circuit model of the noise source impedance is obtained through the measurement, the most effective filter configuration and suitable component values for the built-in power line electromagnetic interference (EMI) filter of the SMPS could be designed with ease.

101 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,514
20223,479
20211,009
20201,579
20191,924
20181,809