Capacitor Research Articles

Electrically Driven Rotation and Nonreciprocal Motion of Microparticles in Nematic Liquid Crystals.

Dispersion of microparticles in nematic liquid crystals offers a novel means for controlling both their orientation and position through the combination of topology and external stimuli. Here, cuboidal and triangular prism shaped microparticles in parallel plate capacitor cells filled with a nematic liquid crystal are studied. Experimental observations are compared with numerical simulations to show that the optimal orientation of the particles is determined by their aspect rations, the relative separation gap of their containers and the applied voltage. It is observed that in systems that allow unrestricted particle rotation, the long axes of the particles are able to fully align themselves with the external electric field. However, when particle rotation is geometrically restricted, it is found that increasing the voltage past a critical value causes the short axis of the particle to realign with the electric field due to anchoring breaking. It is shown that symmetry of the particles then plays a key role in their dynamics following the removal of the electric field, allowing the triangular prisms to travel perpendicular to the applied electric field, whereas only rotation is possible for the cuboidal particles.

A wireless passive extra-arterial implantable blood pressure monitoring sensing system for rats

A novel, wireless, passive, extra-arterial implantable blood pressure monitoring system was designed, fabricated, and tested. The measurement system is composed of an implantable sensor in-vivo and a readout system in-vitro. It was designed to balance the measurement accuracy and arterial invasiveness in continuous blood pressure monitoring. The passive LC resonant circuit was formed by a variable parallel-plate capacitance and a planar spiral inductor. It was fabricated and implanted in the necks of the rats to detect blood pressure changes. The variation of blood pressure was transduced into a change of the capacitance value of the variable parallel-plate capacitor, which caused a variation of the resonant frequency of the LC circuit. A readout probe with inductor coil was then used to measure the change of the resonant frequency of the LC circuit, and therefore indirectly measure the variation of blood pressure wirelessly. By measuring the resonant frequency with electromagnetic coupling of the implanted LC resonant sensor and the external inductor coil, a sensitivity of 8.53 kHz/mmHg for blood pressure measurement had been successfully achieved. The sensing distance is longer than 22 mm, which is enough for implementation of the wireless measurement. The overall size of the implantable sensor is 5 mm × 1.1 mm. The wireless implantable blood pressure sensor may be used in biomedical research for continuous, accurate and arterial trauma free blood pressure monitoring.

Development of “trainer kit kapasitor” (TRAKTOR) as physics learning media based on science process skills (SPS)

This study aimed to discover how the media feasibility and response of a limited trial of Trainer Kit Kapasitor (TRAKTOR)/ Capacitor trainer kit based on Science Process Skills (SPS) as a physics learning media. The method used was research and development (R&D) with the 4-D model. As a physics learning media, TRAKTOR was designed to facilitate some experiment activities, including a experiment in capacitance parallel plate capacitor, circuits of capacitors (series, parallel, series-parallel) charging-emptying capacitor. The results showed that the media is feasible to use, namely, 93.74%, which was categorized as very feasible, and the media obtained students' responses with an excellent category of 85.2%. Based on the result, TRAKTOR can facilitate students' SPS and media suitable for use as a physics learning media.

2D Semiconductor Transistors with Van der Waals Oxide MoO3 as Integrated High‐κ Gate Dielectric

AbstractThe search for smaller electronic and optoelectronic devices is a leading research towards atomically thin graphene‐like 2D semiconductor materials. Due to the decreasing size and unique van der Waals (vdW) nature of these 2D semiconductors, there is an imperative need to find compatible gate dielectrics that can enable high gate coupling efficiency and seamless integration with these materials. One possible approach is to identify and utilize 2D vdW oxides with high dielectric constants, κ, similar to the integration of high‐κ dielectrics HfO2 and ZrO2. To this end, MoO3 is an attractive transition metal oxide candidate for gate dielectrics in 2D field effect transistors (FETs) due to its vdW structure in addition to its high dielectric constant measured in the bulk. This study demonstrates that as‐grown MoO3 has a high dielectric constant, κ, of ≈35 at room temperature at low frequencies by fabricating parallel plate capacitors from these thin flakes. Most importantly, mechanically exfoliated MoO3 nanoflakes are used to create heterostructures with WSe2 and a top‐gate WSe2/MoO3 heterostructure FET is demonstrated, showing the potential of MoO3 as a promising high‐κ 2D vdW gate dielectric.

Single- versus Dual-Ion Conductors for Electric Double Layer Gating: Finite Element Modeling and Hall-Effect Measurements.

Electric double layer (EDL) gating using a single-ion conductor is compared to a dual-ion conductor using both finite element modeling and Hall-effect measurements. Modified Nernst-Planck Poisson (mNPP) equations are used to calculate the ion density per unit area in a parallel plate capacitor geometry with a bulk ion concentration of 215 ≤ cbulk ≤ 1782 mol/m3. With electrodes of equal size at a 2 V potential difference, the EDL ion density of the single-ion conductor is ∼7 × 1013 ions/cm2, which is approximately 50% of the ion density induced in the dual-ion conductor. However, this difference is reduced to 8% when the electrode at which the cationic EDL forms is 10 times smaller than the counter electrode. Thus, for a field-effect transistor gated by a single-ion conductor, it is especially important to have a large gate-to-channel size ratio to achieve strong ion doping. The modeled ion densities are validated by Hall-effect measurements on graphene Hall bars gated by a polyethylene oxide (PEO)-based single-ion conductor. The sheet carrier density, nS, is ∼2 × 1013 cm-2 at Vg = 2 V, which is 3.5 times smaller than the predicted value and has the same order of magnitude as the ns measured for a PEO-based, dual-ion conductor on the same graphene. The numerical modeling results can be approximated by a simple analysis of capacitors in series, where the EDLs are modeled as capacitors with thickness estimated by the sum of the Debye screening length and the Stern layer. The series of capacitor estimate agrees with the numerical modeling of the dual-ion conductor to within 10% and the single-ion conductor to within 30% from 0.25 to 2 V (cbulk = 925 mol/m3); similar agreement is observed in the concentration range of 353-1650 mol/m3 for both single- and dual-ion conductors.

Contactless Stimulation of Multiple Piezoelectric Devices Using Electric Field

The contactless energy transmission scheme using parallel-plate capacitor like structure has been explored which provides a platform for energization of multiple piezoelectric (piezo) components. In the proposed method, ac electric field lines produced by copper electrodes penetrate to the piezo components that are coaxially aligned and positioned in-between at certain distance away from each electrode. Consequently, the components are strongly excited at a point where the functioning electric field source frequency alike with the mechanical resonant frequency of the piezo components. The maximum output power corresponding to optimum load and resonant frequency acquired from the contactless energized multi piezo devices is better than that of power obtained from contactless energized single piezo component by this parallel-plate capacitor electric field generator. The testing results reveal the practicability of non contact stimulation/excitation of multi piezo components simultaneously through electric field.

Investigation into the finger structure capacitor in the micro force measurement device

The finger structure capacitor in the micro force measurement device was investigated by theory model analysis and comparative analysis with traditional parallel plate capacitor. The relationship between the micro force output and the distance variation between the electrodes was analysed. The micro force output of the finger structure capacitor and the traditional parallel plate capacitor were compared. Results show that the finger structure capacitor could produce stable micro force values when the finger structure parameters satisfied with x0/g >5. The output micro force value changed by less than 2% when the distance changed within 1mm in this range. Compared with traditional flat capacitors, the new finger structure capacitor greatly reduced the influence of the measurement and control uncertainty of the distance on the output micro-force values. The new finger structure capacitor device had little change in the output of micro force within 1mm distance variation and its output value changed with 1.7%, under the conditions of different applied voltages.

ANALISIS SENSOR KAPASITIF PELAT SEJAJAR PADA APLIKASINYA SEBAGAI DETEKSI ZAT SATU FASA DAN MULTI FASA

This study uses a pipe/tube-shaped plate capacitive sensor to measure single-phase and multiphase substances to analyze linearity, frequency range, and sensitivity testing. The distance and area of the sensor electrode plate are held constant that and can be viewed from the dielectric material and experimental material. The material or dielectric medium in parallel plate capacitors is a phase consisting of air, aquades, and vegetable oils. Whereas multiphase substances are a combination of air volume, aquades, and vegetable oil. The best linearity analysis results are 0.9467 for aquades + 0.1% NaCl samples and the worst 0.564 for tap-water in layer 1 and the best linearity value is 0.966 for aquades + 0.1% NaCl samples and the most poor 0.5658 is on tap-water at layer 2. The optimal frequency range is at intervals of 500 kHz to 12.5 MHz and the smallest sensitivity test is 500 kHz and the greatest sensitivity is at 12.5 MHz.

Theories for triboelectric nanogenerators: A comprehensive review

Abstract Triboelectric nanogenerators (TENGs) have attracted much attention as energy harvesting and sensor devices. Compared with experimental means, theoretical analysis is of low cost and time-saving for behavior prediction and structural optimization and is more powerful for understanding the working mechanism of TENGs. In this article, the theoretical system for performance simulation of TENGs has been reviewed systematically. The parallel-plate capacitor model, the distance-dependent electric field (DDEF) model, figures of merit (FOMs), and multi-parameter analysis are introduced. The parallel-plate capacitor model is the most fundamental model of TENGs, which is used to simulate the output of TENGs with planar configurations. For non-planar TENGs, the DDEF model is proposed, according to which the electric field is assumed to be distance-dependent rather than being uniform throughout the space. Further, to realize the standardization of TENGs, a series of FOMs are proposed as the standardized evaluation tools for TENGs’ output performance, which are used to reflect the influence of device parameters on the output from different aspects. Lastly, the multi-parameter analysis is introduced to consider the impact of multiple parameters on the output of TENGs simultaneously. These theories constitute the theoretical simulation system of TENGs, which could be used to guide the experimental work on TENGs and boost device optimization in commercial manufacturing.

Simultaneous Piezoelectrocatalytic Hydrogen-Evolution and Degradation of Water Pollutants by Quartz Microrods@Few-Layered MoS2 Hierarchical Heterostructures.

Intense light attenuation in water/wastewater results in photocatalysts exhibiting a low quantum efficiency. This study develops a novel piezoelectrocatalysis system, which involves quartz microrods (MRs) abundantly decorated with active-edge-site MoS2 nanosheets to form a quartz microrods@few-layered MoS2 hierarchical heterostructure (QMSH). Through theoretical calculations, it is found that the quartz MRs serve as a parallel-plate capacitor, which is self-powered to provide an internal electric field to the few-layered MoS2 nanosheets surrounding the quartz MR surfaces, and the piezoelectric potential (piezopotential) effectively facilitates redox reactions with the free carriers in MoS2 . The self-powered quartz MRs in the QMSH present an internal bias to the MoS2 nanosheets, thus yielding a piezoelectrocatalysis system. An efficient piezoelectrocatalytic hydrogen evolution reaction and decomposition of wastewater without light irradiation can be achieved simultaneously. The second-order rate constant of the QMSH is ≈0.631 L mg-1 min-1 , which is 650-fold that of quartz MRs, indicating that the piezoelectric heterostructural catalysts display exceptionally high efficiency on piezoelectrocatalytic redox reactions rather than in the piezocatalytic process. The H2 -production rate of QMSH catalysts approaches ≈6456 µmo1 g-1 h-1 and peaks at ≈16.8 mmol g-1 in 8 h. The piezoelectrocatalytic process may be a promising method for treating industrial wastewater and producing clean energy.

RETRACTED ARTICLE: Synthesis and characterization of trimeric phosphazene based ionic liquids with tetrafluoroborate anions and their thermal investigations

The quaternized compounds (PzIL1–9) reacted with sodium tetrafluoroborate (NaBF4) to generate phosphazene based ionic liquids (PzILs), PzIL1a–9a. The newly synthesized ionic compounds (PzIL1a–9a) were verified using elemental CHN analyses and functional and spectroscopic (FTIR and 1H, 13C, 31P-NMR) analyses techniques. The thermal properties of PzIL1a–9a were investigated using thermogravimetric analysis (TGA). According to the initial decomposition temperature values calculated based on the TGA thermograms, PzIL7a (213 °C) was recognized to be more thermally stable than the other PzILs studied. PzIL1a–9a exhibited good solubility in the water and demonstrate a typical dielectric relaxation behavior, conductivity levels for both low and high-frequency regions. AC conductivity mechanisms and dielectric relaxation behavior of each sample are investigated by fabricating parallel plate capacitors.

Systematic method for studying single-electron transistors

We present a thorough classification of the electronic transport patterns of single-electron transistors (SETs) using a two-letter notation, based on the symmetry properties of SETs and a nondimensionalization procedure. We find five unique symmetry types of SETs: one symmetric and four asymmetric. For these types and the corresponding dimensionless transistor parameter sets, denoted by the two-letter scheme, we calculate and compare current–voltage curves, modulation curves, charge stability diagrams, and the average and standard deviation of the number of excess electrons on the transistor island. The simulation is performed using the mean of the recurrent solution method for the system of kinetic equations for the charge probability distribution function. On the basis of the simulation results, we analyze the properties of asymmetric SETs. We also consider the effect of asymmetry in the transistor bias voltage and show that this effect can be compensated by renormalization of the left and right junction capacitances. In addition, we propose a measurement technique that can be used to determine the voltage bias asymmetry ratio in real experiments. Finally, using the Bardeen approximation for the tunnel matrix element and the parallel-plate capacitor approximation, we estimate the geometric features of the tunnel junctions.

An indirect measurement of the speed of light in a General Physics Laboratory

This paper features an indirect method to measure the speed of light. First, the electrical permittivity of air ε0, is obtained, by using a capacitance meter to measure the capacitance of a parallel-plate capacitor, by varying the separation between its plates. By means of a least squares adjustment, the slope of the straight line is calculated which is related to ε0.Next, the magnetic permittivity of air μ0 is obtained by using a solenoid through which different currents are circulated and the magnetic field is measured in its centre using the Hall sensor of a Smartphone. By means of a least squares adjustment, the slope of the straight line is calculated which is related to μ0.Once ε0 and μ0 have been obtained, the speed of light is calculated by the expression c=1ε0μ0 with its corresponding absolute and relative errors, to verify if the obtained value is compatible with the exact value of c.

Wet chemical synthesis of graphene containing Co / Mn co-doped NiO nanocrystalline materials: Efficient electrode for electrochemical supercapacitors

Graphene containing Co and Mn co-doped NiO nanocrystalline materials (with composition graphene - Ni0.95Co0.025Mn0.025O1-δ) were synthesized by chemical synthesis route and studied for potential application as electrode material for supercapacitors. The phase structure of the materials was characterized by XRD technique and the crystallographic parameters were found out and reported. FTIR spectroscopy revealed the presence of M-O bond in the materials. The morphological phenomenon of the materials was studied by SEM and the particles were found to be in spherical shape with average grain size of 14 – 28 nm. EDAX analysis confirmed the presence of appropriate levels of elements in the samples. The in-depth morphological characteristics were also studied by HR-TEM (High Resolution Tunneling Electron Microscopy). Cyclic voltammetry (CV), charge-discharge and electrochemical impedance measurements were carried-out in an aqueous electrolyte (6 molL-1 KOH) to investigate the electrochemical performance of the graphene containing Co and Mn co-doped NiO nanocrystalline based electrode materials and the material found to exhibit a specific capacitance of 1243 Fg-1 at a current density of 0.5 Ag-1 and hence these electrode materials can be used in electrochemical super capacitors.

Thermo-electro-mechanical behavior of dielectric elastomer actuators: experimental investigations, modeling and simulation

Dielectric Elastomer Actuators (DEAs) are elastic parallel plate capacitors consisting of polymers as dielectric layer and compliant electrodes’. In dynamic applications with high frequencies DEAs heat up. In this work the heating is studied by experimental investigations as well as by modeling of the visco-elastic behavior of the polymer and the specific electric resistance of the electrode and of the polymer. The experimental investigations have also been performed, in order to obtain parameters for the material model. A partially coupled thermo-electro-mechanical material model is presented and used for the numerical simulations. The experimental and numerical results for the time-dependent thermal behavior show an excellent qualitative correlation. This confirms the quality of the developed multi-field model.

A review on the compact modeling of parasitic capacitance: from basic to advanced FETs

This paper presents a review on the development of parasitic-capacitance modeling for metal–oxide–semiconductor field-effect transistors (MOSFETs), covering models developed for the simple parallel-plate capacitance and the nonplanar and coplanar plate capacitances required for the intrinsic and extrinsic part of such devices. A comparative study of various extrinsic capacitance models with respect to a reference model is used to analyze the benefits of the various approaches. Capacitance models for basic MOSFETs and advance multigate FETs with two-dimensional (2D) and three-dimensional (3D) structures are reviewed. It is found that the elliptical field lines between the gate electrodes and source/drain region are modeled very well, while deviations of $$\pm 2 \%$$ in the orthogonal plate capacitance are observed when the gate electrode thickness is varied from 5 to 20 nm .

Patterned rotary parallel-plate capacitor for frequency up-conversion and RC circuit waveform conditioning

This paper details a patterned electrostatic rotary capacitive plate design with high energy densities and provides a novel strategy for up-converting low frequency mechanical excitation sources. The rotating plates allow for output waveform signal conditioning in both control of frequency and waveform shaping. Particular advantages of the rotary plate design with patterned elements include the following: 1) simplicity of design, 2) frequency up-conversion, 3) output waveform signal conditioning, and 4) voltages appropriate for microelectronics. Applications include harvesting energy from environments with complex excitations, especially energy sources with inherently low-frequencies.

Flexoelectric effect on electric potential in piezoelectric graphene-based composite nanowire: Analytical and numerical modelling

In this work, an analytical model was developed to study the distribution of electric potential in a graphene reinforced nanocomposite (GRNC) nanowire. The electromechanical responses such as electric potential and deflection of cylindrical GRNC cantilevered nanowire were investigated. Moreover, the conservative fully coupled finite element (FE) models were developed to validate the analytical predictions. Analytical solution shows that the piezoelectric potential in the GRNC nanowire depends on the transverse force, but it is not a function of the force acting along its axial direction. The electric potential in the tensile and compressive sections of nanowire is antisymmetric along its cross-section, making it as a “parallel plate capacitor” for nanopiezotronics applications such as nanogenerator and piezoelectric field effect transistor due to potential drop across the nanowire which assists as the gate voltage. The predictions of potential distributions across the GRNC nanowire considering piezoelectricity show better agreement with FE predictions. Outcomes of the current work reveal that the flexoelectric effect on the electromechanical behavior of GRNC nanowire is noteworthy and cannot be ignored.

Pengukuran Konstanta Dielektrik Udara Pada Perangkat Kapasitor Plat-Sejajar Berbasis Mikrokontroler Arduino Uno

This study aims to design a prototype of an air dielectric constant measuring device and be able to measure the capacitance value using an Arduino microcontroller device. The measurement of the air dielectric constant is carried out by means of the principle of measuring the capacitance of a capacitor device with a plate-parallel configuration with the air dielectric material. Capacitance measurements are carried out with the principle of charging and emptying capacitors using an Arduino Uno microcontroller device. The charging and discharging process is carried out using a series of resistor-capacitor (RC) series with a source voltage of 5 volts from the microcontroller device. This experiment has used a parallel plate with a size of 29 × 30 cm as an electrode capacitor, and a resistor device with a size of 125 megaOhm. The results showed that the behavior of charging and discharging parallel plate capacitor devices has an R square value of> 0.9, which shows a fairly good correlation between the predicted and experimental results on capacitance measurements. The results showed that the prototype of a dielectric constant measuring device can be well designed by showing the capacitance value of the device at the state of filling and emptying and the measurement results show the value of the air dielectric constant has been measured with a value of 0.991 - 1.0346.

A graphite nanoplatelet-based highly sensitive flexible strain sensor

Flexible strain sensors, as crucial components in smart wearable devices, have recently drawn considerable attention due to their long-term monitoring abilities and facile interaction with the human body. However, low sensitivity, sluggish response, poor repeatability, sophisticated, and expensive fabrication process have notoriously limited their further deep applications. Herein, a graphite nanoplatelet (GNP) based capacitive-type strain sensor has been developed by a cost-effective gap coating method. The prepared sensors can be stretched up to 30%, and unlike other traditional capacitive-type strain sensors which have a limited theoretical maximum gauge factor of 1, it exhibits an interesting negative gauge factor, whose absolute value can go up to ∼3.5. Additionally, this work also investigated the layout design of shunt capacitors, and the pseudo-interdigital capacitor sensor demonstrated a substantial increase in the cyclic stability compared to the parallel plate capacitor. Furthermore, the as-prepared sensor has a fast signal response, whose response time is less than ∼140 ms and recovery time less than ∼90 ms. Also, the cyclic stability test of stretching proves the long-term durability of the sensor. Moreover, a microcontroller unit (MCU) system has been developed in the circuit level to realize the real-time control of a robotic hand.