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1 – 10 of over 2000
Article
Publication date: 30 March 2010

Chen Mei

The purpose of this paper is to develop a capacitance vehicle weighing device. The key part of this device is the capacitance vehicle weighing sensor. This paper discusses…

Abstract

Purpose

The purpose of this paper is to develop a capacitance vehicle weighing device. The key part of this device is the capacitance vehicle weighing sensor. This paper discusses the static and dynamic performance test of capacitance vehicle weighing sensor with emphasis, and provides theoretical analysis, in order to provide the tests and theoretical basis for the popularization and application of the vehicle weighing device.

Design/methodology/approach

The paper gives an introduction to the weighing sensor in respects of the structure design and measuring principles, with the emphasis on the static and dynamic performance of the testing processes. Then, the paper provides the corresponding testing processes and data with theoretical analysis.

Findings

This weighing sensor can be applied to static as well as dynamic tests thus the capacitance vehicle weighing device is practical and worthy of promotion and popularization.

Originality/value

The capacitance vehicle weighing device is characterized by its simple structure, simple measuring circuits, strong reliability in anti‐interference, small size and low cost. The static performance is of little repetitive error, and the use of software may efficiently solve the problems of non‐linearity and hysteresis. In dynamic measurement, the speed, acceleration and vibration of the vehicle produce little effect on the result, which can be neglected, thus being able to overcome the disadvantages of the traditional weighing method which is of low speed and great errors.

Details

Sensor Review, vol. 30 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 5 September 2016

Mani Senthilkumar and L. Ashok Kumar

The purpose of this paper is to design and develop an instrument for non-destructive fabric grams per square metre (GSM) measurement. This study uses the capacitance

Abstract

Purpose

The purpose of this paper is to design and develop an instrument for non-destructive fabric grams per square metre (GSM) measurement. This study uses the capacitance principle to obtain the fabric GSM. The relative permittivity of the sample fabrics changes the capacitance value. A relationship between capacitance and GSM that best fits the look-up table is obtained. Also, the developed system is applicable for all kind of fabrics both knitted and woven fabrics. The comparison study was carried out with existing test method.

Design/methodology/approach

The purpose of the study is to design and develop an instrument for non-destructive fabric GSM measurement.

Findings

The proposed non-destructive method of fabric GSM measurement using capacitance principle is designed, developed and tested. Also, the developed system is applicable for all kind of fabrics both knitted and woven fabrics. The comparison study was carried out with existing test method.

Research limitations/implications

The change in capacitance due to relative permittivity of the sample fabric is in pF range (10-12). The system can be further improved by using a capacitance sensor of sensitivity upto 1 fF (10-15). By doing so, the proposed system provides better results in terms of accuracy and resolution. The system developed can be further extended by making it online equipment which measures the fabric GSM instantaneously.

Originality/value

So far there is no non-destructive testing method available for fabric weight measurement. The newly designed and developed instrument is used to test the fabric both woven and knitted non-destructively.

Details

International Journal of Clothing Science and Technology, vol. 28 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 26 January 2010

Xiaohui Hu and Wuqiang Yang

The purpose of this paper is to present the sensing mechanism, design issues, performance evaluation and applications for planar capacitive sensors. In the context of…

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Abstract

Purpose

The purpose of this paper is to present the sensing mechanism, design issues, performance evaluation and applications for planar capacitive sensors. In the context of characterisation and imaging of a dielectric material under test (MUT), a systematic study of sensor modelling, features and design issues is needed. In addition, the influencing factors on sensitivity distribution, and the effect of conductivity on sensor performance need to be further studied for planar capacitive sensors.

Design/methodology/approach

While analytical methods can provide accurate solutions to sensors of simple geometries, numerical modelling is preferred to obtain sensor response to different design parameters and properties of MUT, and to derive the sensitivity distributions of various electrode designs. Several important parameters have been used to evaluate the response of the sensors in different sensing modes. The designs of different planar capacitive sensor arrays are presented and experimentally evaluated.

Findings

The response features and design guidelines for planar capacitive sensors in different sensing modes have been summarised, showing that the sensor in the transmission mode or the single‐electrode mode is suitable for material characterisation and imaging, while the sensor in the shunt mode is suitable for proximity/displacement measurement. The sensitivity distribution of the sensor depends largely on the geometry of the electrodes. Conductivity causes positive changes for the sensor in the transmission and single‐electrode mode, but negative changes for the sensor in the shunt mode. Experimental results confirm that sensing depths of the sensor arrays and the influence of buried conductor on capacitance measurements are in agreement with simulations.

Research limitations/implications

Experimental verification is needed when a sensor is designed.

Originality/value

This paper provides a comprehensive study for planar capacitive sensors in terms of sensor design, evaluation and applications.

Details

Sensor Review, vol. 30 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Abstract

Purpose

This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation.

Design/methodology/approach

The capability of both, sensing and manipulation was analysed based on capacitance changes corresponding to the particle positioning and stationing of the targeted particles at regions of interest. The mechanisms of DEP sensor and actuator, designed in DOC applications were energized by electric field of tapered DEP microelectrodes. The actual DEP forces behaviour has been also studied via quantitative analysis of capacitance measurement value and its correlation with qualitative analysis of positioning and stationing of targeted particles.

Findings

The significance of the present work is the ability of using tapered DEP microelectrodes in a closed mode system to simultaneously sense and vary the magnitude of manipulation.

Originality/value

The integration of DOC platform for contactless electrical-driven with selective detection and rapid manipulation can provide better efficiency in in situ selective biosensors or bio-detection and rapid bio-manipulation for DOC diagnostic and prognostic devices.

Details

Microelectronics International, vol. 37 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 9 November 2015

Alexander Sergeevich Tonkoshkur and Alexander Vladimirovich Ivanchenko

– The purpose of this paper is modeling the effect of negative capacitance in the capacitance-voltage characteristic of the intergranular potential barrier of varistor structure.

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Abstract

Purpose

The purpose of this paper is modeling the effect of negative capacitance in the capacitance-voltage characteristic of the intergranular potential barrier of varistor structure.

Design/methodology/approach

The modeling of the capacitance-voltage characteristic of the intergranular barrier in metal oxide varistor ceramics is based on the development of the algorithm. It includes all the known mechanisms of electrotransfer in a wide range of voltages and currents, and also takes into account the voltage drop on the intergranular interlayer of intergranular potential barrier.

Findings

The models and algorithms for calculating the capacitance-voltage characteristics of a single intergranular potential barrier with the use of the most established understanding used at the interpretation of the nonlinear conductivity intergranular barrier are developed. The results of the capacitance-voltage characteristics modeling correspond to the existing understanding of the electrical properties on the ac current varistor ceramics are based on zinc oxide. The model allows to predict the behavior of varistors on the alternating current (voltage).

Originality/value

It is established that the recharge of the surface localized states occurs when a voltage is applied to the varistor structure, it can lead to a relaxation decrease in the width of the potential barrier overcome by tunneling electrons in the field emission from the conduction band of the one crystallite in the conduction band of the other crystallite and thus to the current backlog of applied voltage on the phase (i.e. the expression of the negative capacitance effect).

Details

Multidiscipline Modeling in Materials and Structures, vol. 11 no. 4
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 31 December 2019

Sathies Thangavel and Senthil Ponnusamy

The purpose of this study is to demonstrate the usage of three-dimensionally (3D) printed polylactic acid (PLA)-carbon black (CB) conductive polymer composite in the…

Abstract

Purpose

The purpose of this study is to demonstrate the usage of three-dimensionally (3D) printed polylactic acid (PLA)-carbon black (CB) conductive polymer composite in the measurement of the void fraction and liquid level.

Design/methodology/approach

PLA-CB conductive polymer composite is 3D printed through fused deposition modelling (FDM) technique and used as a capacitive sensor for void fraction measurement and liquid level sensing. The sensitivity of 3D printed ring and concave type capacitive sensors are compared for void fraction measurement. The effect of electrode length, thickness and pipe dimension on the capacitance achievable for the particular void fraction is studied. Concept of fringing capacitance is used for the sensing of liquid level.

Findings

Compared to the concave design comprising four electrodes, the ring-type capacitive sensor produced better results in void fraction measurement. Increase in pipe diameter and electrode length results in the enhancement of capacitance arising from specific void fraction. For a 100 mm diameter pipe, the capacitance of the 150 mm-long concave electrode (0.4 mm thick) increased from 9.98 to 67.77 pF as the void fraction decreased from 100% to 0%. Development of the fringing capacitance in 3D printed PLA-CB composite helps in the measurement of liquid level. Both parallel finger topology and interdigital electrode configuration are able to sense the liquid level.

Originality/value

Ability of the 3D printed conductive PLA-CB composite to act as a capacitive sensor is experimentally analysed. Performance of different electrode configuration is tested for both void fraction measurement and liquid level sensing. Results of experimentation prove that FDM printed PLA-CB composite is suitable for the void fraction and liquid level measurement.

Details

Sensor Review, vol. 40 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 24 March 2022

Yi Huang and Xi Chen

This paper aims to characterize the relationship between the interelectrode capacitance (C) of metal-oxide-semiconductor field-effect transistors (MOSFETs) and the applied…

Abstract

Purpose

This paper aims to characterize the relationship between the interelectrode capacitance (C) of metal-oxide-semiconductor field-effect transistors (MOSFETs) and the applied bias voltage (V) by a fractional-order equivalent model.

Design/methodology/approach

A Riemann–Liouville-type fractional-order equivalent model is proposed for the CV characteristic of MOSFETs, which is based on the mathematical relationship between fractional calculus and the semiconductor physical model for the interelectrode capacitance of metal oxide semiconductor structure. The CV characteristic data of an N-channel MOSFET are obtained by Silvaco TCAD simulation. A differential evolution-based offline scheme is exploited for the parameter identification of the proposed model.

Findings

According to the results of theoretical analysis, mathematical derivation, simulation and comparison, this paper illustrates that, along with the variation of bias voltage applied, the interelectrode capacitance (C) of MOSFETs performs a fractional-order characteristic.

Originality/value

This work uncovers the fractional-order characteristic of MOSFETs’ interelectrode capacitance. By the proposed model, the influence of doping concentration on the gate leakage parasitic capacitance of MOSFETs can be revealed. In the pre-defined doping concentration range, the relative error of the proposed model is less than 5% for the description of CV characteristics of metal-oxide-semiconductor field-effect transistors (MOSFETs). Compared to some existing models, the proposed model has advantages in both model accuracy and model complexity, and the variation of model parameters can directly reflect the relationship between the characteristics of MOSFETs and the doping concentration of materials. Accordingly, the proposed model can be used for the microcosmic mechanism analysis of MOSFETs. The results of the analysis produce evidence for the widespread existence of fractional-order characteristics in the physical world.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 41 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 10 August 2018

Baogang Wen, Hongjun Ren, Pengfei Dang, Xu Hao and Qingkai Han

The oil film thickness provides a key performance indicator of a ball bearing lubrication condition. This paper aims to propose an approach to calculate and measure the…

Abstract

Purpose

The oil film thickness provides a key performance indicator of a ball bearing lubrication condition. This paper aims to propose an approach to calculate and measure the oil film thickness of the bearing.

Design/methodology/approach

On a specially designed test rig, measurement of the capacitance is used to monitor the oil film thickness of ball bearing. A corrected film thickness formula taking account of the influences of non-Newtonian shear thinning and thermal is introduced to predict the oil film thickness of ball bearing. And then the film thickness distribution and the corresponding capacitances are calculated.

Findings

Measurement and calculation of oil film thickness in a ball bearing are carried out under various rotating speeds and external loads. By comparing the calculated capacitances with measured results, it can be concluded that the calculated results obtained by the amended film thickness formula are much closer to the test findings than the classical computed values according to Hamrock–Dowson.

Originality/value

A new corrected film thickness formula is introduced in predicting oil film thickness of ball bearing and verified by the series of experiments according to capacitance method.

Details

Industrial Lubrication and Tribology, vol. 70 no. 8
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 26 August 2014

Damir Krklješ, Dragana Vasiljević and Goran Stojanović

This paper aims to present a prototype of a capacitive angular-position sensor which exploits advantages of flexible/printed electronics. The novelty of the sensor is that…

Abstract

Purpose

This paper aims to present a prototype of a capacitive angular-position sensor which exploits advantages of flexible/printed electronics. The novelty of the sensor is that the capacitor structure is placed at the circumference of the rotor and stator, that it posses two channels (capacitor structures) electrically shifted for p/4 and that the rotor is common for both channels. The electrodes of the sensing capacitor are digitated, providing a triangular transfer function.

Design/methodology/approach

This sensor prototype consists of two flexible inkjet-printed silver electrodes forming a cylindrical capacitor structure. One of them is wrapped around the stator and another is wrapped around the rotor part of a simple mechanical platform used to precisely adjust the angular displacement.

Findings

The capacitance as a function of angular position was measured using an inductance capacitance impedance (LCZ) Meter, and results are presented for a full-turn measurement range. The experimental results are compared with analytical ones and very good agreement has been achieved.

Originality/value

The proposed capacitive sensor structure can be used as an absolute or an incremental encoder with different resolutions, and it can be applied in automotive industry or robotics.

Details

Sensor Review, vol. 34 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 11 May 2012

Owen Thomas, Martin Wickham and Chris Hunt

The purpose of this paper is to present work on the incorporation of capacitors into printed circuit boards (PCB) as a method to measure moisture content and follow…

Abstract

Purpose

The purpose of this paper is to present work on the incorporation of capacitors into printed circuit boards (PCB) as a method to measure moisture content and follow moisture diffusion under ground planes.

Design/methodology/approach

PCBs were manufactured of FR‐4 incorporating different arrangements and sizes of capacitors formed between the tracks on adjacent layers of the PCB. The boards were placed in an 85°C and 85 per cent relative humidity (RH) environment to absorb moisture before baking at temperatures of 80, 110 or 125°C with the capacitance periodically measured. The effect of ground planes with different densities of plated and non‐plated through holes (PTH) has been studied by placing capacitors between ground planes.

Findings

Parallel plate capacitors embedded within a PCB showed a 10 per cent capacitance increase going from a dry state to being saturated with moisture in an 85°C and 85 per cent RH environment. The slow ingression of moisture under the capacitance planes meant that the measured capacitance change did not reflect the moisture content of the remainder of the board well. Capacitor plates with slots for the moisture to penetrate were also investigated, with the increase in capacitance found to show good correlation with the increase in board mass. In investigating moisture under ground planes, either by decreasing the hole density or by plating the holes, the time for moisture to diffuse out of the board was found to increase due to the lower exposed area on the PCB.

Originality/value

The paper illustrates a method that can be applied to PCB manufacturing to assess the moisture content of a board prior to reflow.

Details

Circuit World, vol. 38 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

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