Circuit Elements Research Articles

Numerical Stability of Dual Full-Wave Formulations With Electric Circuit Element Boundary Conditions

Numerical Stability of Dual Full-Wave Formulations With Electric Circuit Element Boundary Conditions

Predictive Processing: A Circuit Approach to Psychosis.

Predictive processing is a computational framework that aims to explain how the brain processes sensory information by making predictions about the environment and minimizing prediction errors. It can also be used to explain some of the key symptoms of psychotic disorders such as schizophrenia. In recent years, substantial advances have been made in our understanding of the neuronal circuitry that underlies predictive processing in cortex. In this review, we summarize these findings and how they might relate to psychosis and to observed cell type-specific effects of antipsychotic drugs. We argue that quantifying the effects of antipsychotic drugs on specific neuronal circuit elements is a promising approach to understanding not only the mechanism of action of antipsychotic drugs but also psychosis. Finally, we outline some of the key experiments that should be done. The aims of this review are to provide an overview of the current circuit-based approaches to psychosis and to encourage further research in this direction.

High-order sensory processing nanocircuit based on coupled VO2 oscillators

Conventional circuit elements are constrained by limitations in area and power efficiency at processing physical signals. Recently, researchers have delved into high-order dynamics and coupled oscillation dynamics utilizing Mott devices, revealing potent nonlinear computing capabilities. However, the intricate yet manageable population dynamics of multiple artificial sensory neurons with spatiotemporal coupling remain unexplored. Here, we present an experimental hardware demonstration featuring a capacitance-coupled VO2 phase-change oscillatory network. This network serves as a continuous-time dynamic system for sensory pre-processing and encodes information in phase differences. Besides, a decision-making module for special post-processing through software simulation is designed to complete a bio-inspired dynamic sensory system. Our experiments provide compelling evidence that this transistor-free coupling network excels in sensory processing tasks such as touch recognition and gesture recognition, achieving significant advantages of fewer devices and lower energy-delay-product compared to conventional methods. This work paves the way towards an efficient and compact neuromorphic sensory system based on nano-scale nonlinear dynamics.

Engineering qubit coupling to reservoir mode: Optimizing circuitry to extend coherence time

The research investigates how reservoir modes influence the decay and dephasing rates of a qubit, utilizing a circuit model where the qubit interacts with N distinct oscillators. The Lagrangian and Hamiltonian of the system are deduced theoretically, and the analysis delves into how circuit components like the qubit and coupling capacitors affect the decay rate. Notably, the study reveals that the coupling capacitor exerts a more pronounced influence on the relaxation time compared to the qubit capacitor. Moreover, it quantifies the repercussions of bosonic modes affected by coupling to reservoir modes on the qubit coherence time. As a result, the primary objective of the investigation is to examine the impact of circuit elements on qubit behavior, offering valuable insights into the determinants of qubit decay and dephasing rates.

A fast and structurally simple control scheme based on a fuzzy supervisory approach for wireless power transfer systems

AbstractWireless power transfer (WPT) is a promising technology and has attracted many researchers’ attention due to its inherent advantages such as reliability, safety, flexibility, and low maintenance costs. For WPT systems, the output voltage varies according to the variable loads and the coupling coefficient conditions, affecting system stability and efficiency. In this regard, this study is concerned with the tracking control problem of WPT systems based on fuzzy supervisory proportional–integral (PI) controller and a phase shift modulation technique, which is for the first time proposed by this paper. By introducing appropriate fuzzy rules, the proposed control scheme not only can track the desired output voltage but also has better robust behaviour to deal with the problem of variations of circuit elements and coupling coefficients. That is, the proposed fuzzy supervisory PI control scheme can perform better than the traditional PI controller. Analysis of the designed control method and simulation results validate the superiority of the proposed method over the traditional PI controller in all conditions, which can make it a suitable choice for the applications of electric vehicle charging systems. The analysis is supported by experimental measurements.

Optimizing for periodicity: a model-independent approach to flux crosstalk calibration for superconducting circuits

Flux tunability is an important engineering resource for superconducting circuits. Large-scale quantum computers based on flux-tunable superconducting circuits face the problem of flux crosstalk, which needs to be accurately calibrated to realize high-fidelity quantum operations. Typical calibration methods either assume that circuit elements can be effectively decoupled and simple models can be applied, or require a large amount of data. Such methods become ineffective as the system size increases and circuit interactions become stronger. Here we propose a new method for calibrating flux crosstalk, which is independent of the underlying circuit model. Using the fundamental property that superconducting circuits respond periodically to external fluxes, crosstalk calibration of N flux channels can be treated as N independent optimization problems, with the objective functions being the periodicity of a measured signal depending on the compensation parameters. We demonstrate this method on a small-scale quantum annealing circuit based on superconducting flux qubits, achieving comparable accuracy with previous methods. We also show that the objective function usually has a nearly convex landscape, allowing efficient optimization.

ВИЗНАЧЕННЯ ТА АНАЛІЗ РОБОЧИХ ХАРАКТЕРИСТИК ВИСОКОВОЛЬТНИХ ЕЛЕКТРОТЕХНІЧНИХ СИСТЕМ НА ОСНОВІ ПОСЛІДОВНОГО ВИСОКОДОБРОТНОГО РЕЗОНАНСНОГО LC-КОНТУРУ

The paper analyzes the performance characteristics of the electrоtechnical system (ETS), built on the basis of a series high-Q resonant LC circuit and intended for diagnosing the isolation of high-voltage equipment. The frequency dependences of the parameters L and C elements of the resonant circuit were experimentally studied and it was shown that for both elements there is an optimal frequency at which the value of the element’s Q- factor reaches its maximum value. It was established that the Q-factor of the investigated circuit is determined mainly by the Q-factor of its inductance and reaches the maximum value QLC,max = 280 at the frequency f= 40 kHz. The Simulink model was developed for the analysis of the performance characteristics of the ETS in steady state. Graphical dependences are given, which allow to determine the level of voltage on the load for a given active resistance of this load, as well as the energy characteristics and the value of the efficiency of the ETS at the stage of its design. A Simulink model has also been developed to analyze the dynamic characteristics of the ETS when a breakdown of the diagnosed insulation occurs. It is shown that the breakdown of the insulation in the ETS, which has a series high-Q resonant circuit, will cause a rapid decrease in current by Q times, and not an increase in current to emergency values, as in an ETS based on high-voltage transformers. In this way, a fast-acting parametric stabilization of the output current is implemented in the ETS even in case of electrical breakdowns of the high-voltage insulation of the power equipment under diagnosis. Thus, the ETS implements high-speed parametric stabilization of the output current, which prevents the destruction of both the ETS and the diagnosed high-voltage insulation of power equipment even during its electrical breakdown. References 11, figures 9.

Effective Gating in Single-Molecule Junctions through Fano Resonances.

The successful incorporation of molecules as active circuit elements relies on the ability to tune their electronic properties through chemical design. A synthetic strategy that has been used to manipulate and gate circuit conductance involves attaching a pendant substituent along the molecular conduction pathway. However, such a chemical gate has not yet been shown to significantly modify conductance. Here, we report a novel series of triarylmethylium and triangulenium carbocations gated by different substituents coupled to the delocalized conducting orbitals on the molecular backbone through a Fano resonance. By changing the pendant substituents to modulate the position of the Fano resonance and its coupling to the conducting orbitals, we can regulate the junction conductance by a remarkable factor of 450. This work thus provides a new design principle to enable effective chemical gating of single-molecule devices toward effective molecular transistors.

An optoelectronic Coupler based on graphene patterns and SU-8 photoresist

PurposeThe purpose of this research is to efficiently separate incident terahertz (THz) waves into distinct transmission and reflection channels by minimizing the absorption ratio. So, the optical systems operating within the THz frequency range can developed. To achieve a multi-band response, four different periodic arrays of graphene patterns are used. These arrays are strategically stacked on both sides of three SU-8 photoresists, serving as dielectric materials. Consequently, each layer exhibits a unique influence on the device's response, and by applying four external bias voltages, the behavior of the device can be precisely controlled and adjusted.Design/methodology/approachA novel optoelectronic device operating in the THz frequency range is introduced, using periodic arrays of graphene patterns and SU-8 photoresist dielectrics. The design of this device is based on meta-surface principles, using both the equivalent circuit model (ECM) and transmission line concept. The output of the device is a THz coupler implemented by analyzing the reflection and transmission channels. The structure is characterized using the ECM and validated through comprehensive full-wave simulations. By representing the electromagnetic phenomenon with passive circuit elements, enabling the calculation of absorption, reflection and transmission through the application of the theory of maximum power transfer.FindingsBased on simulation results and theoretical analysis, the proposed device exhibits sensitivity to gate biasing, enabling efficient reflection and transmission of THz waves. The device achieves reflection and transmission peaks exceeding across the five distinct THz bands 90%, and its behavior can be tuned by external gate biasing. Moreover, the device's sensitivity to variations in geometrical parameters and chemical potentials demonstrates its reliable performance. With its outstanding performance, this high-performance meta-surface emerges as an ideal candidate for fundamental building blocks in larger optical systems, including sensors and detectors, operating within the THz frequency band.Originality/valueThe proposed device covers a significant portion of the THz gap through the provision of five adjustable peaks for reflection and transmission channels. Additionally, the ECM and impedance matching concept offers a simplified and time-efficient approach to designing the meta-surface. Leveraging this approach, the proposed device is effectively represented using passive circuit elements such as inductors, capacitors and resistors, while its performance is validated through the utilization of the finite element method (FEM) as a full-wave simulation tool. This combination of circuit modeling and FEM simulation contributes to the robustness and accuracy of the device's performance evaluation.

Modeling and applications of Electrochemical Impedance Spectroscopy (EIS) for Zinc-ion batteries

Electrochemical Impedance Spectroscopy (EIS) has emerged as a valuable tool for evaluating secondary batteries due to their efficiency and accuracy. However, interpreting the multifaceted impedance spectra derived from EIS demands a comprehensive grasp of the electrochemical context. This study focuses on devising and applying an Electrochemical Impedance Spectroscopy (EIS) model customized specifically for deciphering the intricacies of zinc-ion batteries. The model construction is tailored to the battery's complexities, enabling extraction of circuit elements that faithfully depict the system's dynamics. Moreover, this research investigates the relationship between parameters of the governing equations. Through experimental validation employing real-time EIS measurements from a zinc-ion battery prototype, the reliability and efficacy of the proposed model are confirmed. This validated model not only enhances our understanding of zinc-ion battery behavior but also propels advancements in utilizing this technology across various energy storage applications.

Charging and discharging a supercapacitor in molecular simulations.

As the world moves more toward unpredictable renewable energy sources, better energy storage devices are required. Supercapacitors are a promising technology to meet the demand for short-term, high-power energy storage. Clearly, understanding their charging and discharging behaviors is essential to improving the technology. Molecular Dynamics (MD) simulations provide microscopic insights into the complex interplay between the dynamics of the ions in the electrolyte and the evolution of the charge distributions on the electrodes. Traditional MD simulations of (dis)charging supercapacitors impose a pre-determined evolving voltage difference between the electrodes, using the Constant Potential Method (CPM). Here, we present an alternative method that explicitly simulates the charge flow to and from the electrodes. For a disconnected capacitor, i.e., an open circuit, the charges are allowed to redistribute within each electrode while the sum charges on both electrodes remain constant. We demonstrate, for a model capacitor containing an aqueous salt solution, that this method recovers the charge-potential curve of CPM simulations. The equilibrium voltage fluctuations are related to the differential capacitance. We next simulate a closed circuit by introducing equations of motion for the sum charges, by explicitly accounting for the external circuit element(s). Charging and discharging of the model supercapacitor via a resistance proceed by double exponential processes, supplementing the usual time scale set by the electrolyte dynamics with a novel time scale set by the external circuit. Finally, we propose a simple equivalent circuit that reproduces the main characteristics of this supercapacitor.

Smartphone Fast Charger Analysis Based on RLC Circuit Transient Process

In today's era, the widespread adoption of mobile terminals, particularly smartphones, has been facilitated by the rapid advancements in information and communication technology. However, a notable drawback of smartphones is their high-power consumption, necessitating faster charging solutions to enhance user convenience. This paper focuses on the RLC circuit of fast chargers. Initially, it introduces the fundamental principles and associated protocols of fast charging technology, elucidating the operation of integrated circuits within fast chargers and highlighting the advantages of fast charging compared to conventional slow charging methods. Moreover, the paper conducts an in-depth analysis of the transient processes within the pivotal series RLC circuit in fast chargers, encompassing zero-input responses and sinusoidal AC excitation responses. The transient processes are categorized into overdamped, critically damped, or underdamped states based on circuit element parameters, with initial conditions and power supply phase determining whether the circuit transitions directly into a steady-state process when stimulated by sinusoidal AC. This research contributes to a deeper understanding of the RLC circuit within smartphone fast chargers and serves as a valuable reference for advancing the development of fast charging solutions.

Insulation of feed water tank in arrangement of transportable boiler plant with direct-flow steam boiler

A transportable boiler plant is used to provide consumers with steam of high energy characteristics, while saving costs for the construction of stationary boiler houses. A transportable boiler plant can be placed in the conditions of the Far North on an oilfield site. It is therefore necessary to organize reliable and safe operation of the boiler house, consisting of a steam direct-flow boiler of the coil type, a feed pump, a feed water tank and other auxiliary elements of the thermal circuit. One of the important elements in the thermal circuit is the feed water tank, in which water accumulates after chemical purification. It is where the water is also heated, increasing the efficiency of the boiler. Methods for calculating the diameters of main steam pipelines and feed water pipelines are described. The theoretical foundations of the operation of the feed water tank, its use in thermal power plants, combined heat and power plants, district industrial and heating boilers using various thermal arrangements of the above-mentioned enterprises are considered. The operation of the feed water tank in the thermal circuit of a steam unit is discussed. A thermal circuit of an industrial boiler house has been designed to generate saturated steam for consumers using direct-flow steam boilers of the coil type. The diameters of the inlet and outlet pipelines of the storage tank are calculated. The effective thickness of thermal insulation required to minimize heat losses during operation of a transportable boiler plant has been determined. Modeling of the design of the feed water tank and heat losses through its surface is carried out. A 3D model of the designed tank is presented, as well as heat losses through the surface of the tank walls when using a thermal insulation material. The importance of using thermal insulation of various tanks for storing feed water, petroleum products, hydrocarbons and other various media is noted.

Sawtooth Signal Generator Using a Carbon-Based Memristor

It is possible to use the new electronic circuit element memristor in analog applications. Memristors or memristor emulators have already been applied in analog applications such as amplifiers, filters, oscillators, and chaotic circuits. In literature, it has been recently demonstrated that a memristor-based sawtooth signal generator can be built utilizing a memristor emulator and simulations with various memristor models. Such a sawtooth signal generator needs experimental verification with a memristor. Self-Directed Channel (SDC) Carbon-based Memristors are in the market now. Once, the memristor technology is mature enough, its applications may also follow soon. Any memristor application should be realized with a memristor, not an emulator. Knowm memristor has not been used to design a sawtooth signal generator in the literature previously. The aim of the study is to show that a sawtooth signal generator can be made using a Self-Directed Channel (SDC) Carbon-based Memristor and to examine it experimentally. The performance of this sawtooth signal generator is evaluated. The waveforms of the proposed circuit are also examined by varying its operating frequency. The simulation and experimental results are compared. It has been found that its waveforms can be predicted well up to 350 kHz and its high-frequency behavior is not predicted well above 350 kHz by the memristor model used.

Numerical impedance matching via extremum seeking control of single-frequency capacitively coupled plasmas

Abstract Impedance matching is a critical component of semiconductor plasma processing for minimizing the reflected power and maximizing the plasma absorption power. In this work, a more realistic plasma model is proposed that couples lumped element circuit, transmission line, and particle-in-cell (PIC) models, along with a modified gradient descent algorithm (GD), to study the impact of presets on the automatic matching process. The effectiveness of the proposed conceptual method is validated by using a single-frequency capacitively coupled plasma as an example. The optimization process with the electrode voltage and the reflection coefficient as the objective function and the optimized state, including plasma parameters, circuit waveforms, and voltage and current on transmission lines, is provided. These results show that the presets, such as initial conditions and objective functions, are closely related to the automatic matching process, resulting in different convergence speeds and optimization results, proving the existence of saddle points in the matching network parameter space. These findings provide valuable information for future experimental and numerical studies in this field.

Inverse design of high-dimensional quantum optical circuits in a complex medium

Programmable optical circuits are an important tool in developing quantum technologies such as transceivers for quantum communication and integrated photonic chips for quantum information processing. Maintaining precise control over every individual component becomes challenging at large scales, leading to a reduction in the quality of operations performed. In parallel, minor imperfections in circuit fabrication are amplified in this regime, dramatically inhibiting their performance. Here we use inverse design techniques to embed optical circuits in the higher-dimensional space of a large, ambient mode mixer such as a commercial multimode fibre. This approach allows us to forgo control over each individual circuit element, and retain a high degree of programmability. We use our circuits as quantum gates to manipulate high-dimensional spatial-mode entanglement in up to seven dimensions. Their programmability allows us to turn a multimode fibre into a generalized multioutcome measurement device, allowing us to both transport and certify entanglement within the transmission channel. With the support of numerical simulations, we show that our method is a scalable approach to obtaining high circuit fidelity with a low circuit depth by harnessing the resource of a high-dimensional mode mixer.

Hidden schematics of EMI filters

The paper presents the lumped parameters of EMI filters that must be used in the design process. In order to obtain consistent results, apart from the conventional parameters and stress de-rating factors (power dissipation, limiting voltage and current, operating temperature range, etc.), one should think also in terms of nonideal behaviour of the circuit elements in the equivalent model. Following this conduct the calculated filter characteristics (attenuation or insertion loss) will gain in accuracy.

E-Suture: Mixed-Conducting Suture for Medical Devices.

Modern implantable bioelectronics demand soft, biocompatible components that make robust, low-impedance connections with the body and circuit elements. Concurrently, such technologies must demonstrate high efficiency, with the ability to interface between the body's ionic and external electronic charge carriers. Here, a mixed-conducting suture, the e-suture,is presented. Composed of silk, the conducting polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), and insulating jacketing polymers,the resulting e-suture has mixed-conducting properties at the interface with biological tissue as well as effective insulation along its length. The e-suture can be mechanically integrated into electronics, enabling the acquisition of biopotentials such as electrocardiograms, electromyograms, and local field potentials (LFP). Chronic, in vivo acquisition of LFP with e-sutures remains stable for months with robust brain activity patterns. Furthermore, e-sutures can establish electrophoretic-based local drug delivery, potentially offering enhanced anatomical targeting and decreased side effects associated with systemic administration, while maintaining an electrically conducting interface for biopotential monitoring. E-sutures expand on the conventional role of sutures and wires by providing a soft, biocompatible, and mechanically sound structure that additionally has multifunctional capacity for sensing, stimulation, and drug delivery.

A systematic management and control methodology for high energy saving in applications equipped with hydraulic servo-axes

A systematic methodology for the real-time improvement of the overall efficiency of applications using hydraulic servo-axes is presented. The proposed methodology introduces three modules: a hydraulic actuator load estimator, a hydraulic energy optimizer and a controlled hydraulic power supply; these are discussed at the theoretical and application level. The proposed approach reduces the power losses across the main elements of the hydraulic circuit, leading to high energy savings and introducing a new guideline on managing and controlling the servo hydraulic actuator. The methodology is applicable to any application using hydraulic servo-axis systems, and therefore it is not tailored to a particular field. Its performances have been evaluated in different industrial case studies (a blanking press, a drawing press and a die-casting plant) through numerical simulations. Conspicuous energy savings, ranging between 59% and 88%, have been obtained in simulation, suggesting that a significant carbon footprint reduction for energy-intensive hydraulic machinery is achievable in a wide range of applications.

Simplified thermal model for open type 1.5 kW synchronous reluctance motor using thermal equivalent circuit and finite element method

In this study, two thermal models, the thermal equivalent circuit (TEC) and finite element method (FEM), were used for the transient thermal analysis of an open-type synchronous reluctance motor. Both the transient TEC method and the FEM were carried out for longer than 3 h after the motor was driven to reach a steady state. The results were compared with experimental results to verify the feasibility of the two thermal models. When the experimental results were compared with the TEC method results, the average temperature difference of all the parts was within 9 %. When the experimental and FEM results were compared, the average temperature difference of all the parts was within 7 %. Therefore, both thermal models are suitable for predicting the motor temperature.