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Kaushal Kishore

Bio: Kaushal Kishore is an academic researcher from Academy of Scientific and Innovative Research. The author has contributed to research in topics: Capacitive sensing & Current conveyor. The author has an hindex of 6, co-authored 25 publications receiving 112 citations. Previous affiliations of Kaushal Kishore include Council of Scientific and Industrial Research & Central Electronics Engineering Research Institute.

Papers
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Journal ArticleDOI
TL;DR: In this article, a simple and accurate impedance measurement technique (IMT) for wide range lossy capacitive sensor is proposed, which is based on the separation of in-phase and quadrature components.
Abstract: In this paper, a new, simple and accurate impedance measurement technique (IMT) for wide range lossy capacitive sensor is proposed. The proposed technique accepts sensors having capacitance ‘Cx’ with lossy resistance ‘Rx’ in parallel. The proposed IMT is based on the separation of in-phase and quadrature components, which is achieved by using phase to time converter. For comparative study, two circuit configurations are proposed. In first proposed solution, the sensor parameters are measured by separating the real and imaginary part of the output electrical signal. In the second proposed configuration, the measurement range is enhanced using an auto-balancing approach, which is achieved by monitoring phase difference between input and output voltages. Experimental evaluation of the proposed configurations reveals that the first configuration is able to estimate the sensor capacitance in the range 200–1200 pF and lossy resistance in the range of 100 kΩ–1.2 MΩ with a maximum error of 6%. The second configuration exhibits an enhanced range of 100–2000 pF for sensor capacitance and 33 kΩ–3 MΩ for lossy resistance with a maximum error of 5%. The IMT was interfaced with a fabricated γ-Al2O3 based impedance humidity sensor, measured its Cx (70 pF–800 pF) and Rx (35 kΩ–4 MΩ) at different concentration of humidity, calculated the humidity, and compared its performance with existing techniques, showing the practicality of the proposed IMT.

43 citations

Journal ArticleDOI
TL;DR: A brief history of phase-sensitive detection leading up to the state-of-the-art implementation in various fields of application is put forward and different designs and implementation techniques for LIA have been categorized and introduced as per the design topologies.
Abstract: The phase-sensitive detection (PSD), popularly referred to as lock-in amplifier (LIA) has been around for quite a long time. Lock-in amplifier has been quite a versatile measurement instrument for extracting low-level signals buried in noise. In the recent past, the importance of LIA has been realized as a sensor interfacing platform and a number of portable implementations targeting sensing applications have been reported. This review surveys LIA design, implementation and application as portable sensor interfaces. The paper put forward a brief history of phase-sensitive detection leading up to the state-of-the-art implementation in various fields of application. Different designs and implementation techniques for LIA have been categorized and introduced as per the design topologies. The main category being analog, digital, FPGA and CMOS integrated design. Finally, the application of LIA in resistive, capacitive, impedance, optical and Nano-bio sensors is categorized and investigated in detail.

41 citations

Proceedings ArticleDOI
01 Feb 2016
TL;DR: In this article, a novel Current-Mode (CM) square/triangular wave oscillator, based on second generation current conveyor (CCII), operating as resistance/capacitance to time conversion is described.
Abstract: In this paper, a novel Current-Mode (CM) square/triangular wave oscillator, based on second generation current conveyor (CCII), operating as resistance/capacitance to time conversion is described. The proposed oscillator, which consists of two CCII as an active element, three grounded resistances and one capacitance found to be an effective alternate of voltage mode based interfaces for wide range capacitive and resistive sensors. The interface circuit was implemented with commercially available current feedback operational amplifier AD844 from Analog Devices and passive components. Experimental results confirmed the theoretical expectations, showing good linearity in wide oscillation frequency/period range, which can be independently adjusted through resistive or capacitive external passive components. Experimental measurement was also conducted on a fabricated capacitive humidity sensor to verify the real time application of the proposed interface circuit. The interface circuit has shown a good accuracy and linearity for wide variation in capacitance of humidity sensor.

16 citations

Journal ArticleDOI
TL;DR: Analog signal conditioning circuit based on dual differential subtractor for wide range resistive measurement of single element resistive sensor is presented in this paper, which helps to achieve high accuracy and wide dynamic range by generating a control voltage proportional to the sensor resistance.
Abstract: Analog signal conditioning circuit based on dual differential subtractor for wide range resistive measurement of single element resistive sensor is presented in this paper. The differential output from the sensor and a voltage-controlled reference resistor is followed by an auto-nulling technique, which helps to achieve high accuracy and wide dynamic range by generating a control voltage proportional to the sensor resistance. The presented automatic approach not only enhances the auto-nulling range but also ensures constant sensitivity. The interface design provides high accuracy, fast and linear response at the same time avoids drawbacks of lead wire variations. A prototype PCB of the proposed circuit is fabricated and tested. The experimental result shows that the circuit can measure a wide range of resistance (20 $\text{k}\Omega $ - 1.1 $\text{M}\Omega$ ) with relative error less than 0.78%, compared to other bridge-based circuits which are capable of measuring the maximum resistance of up-to 10 $\text{k}\Omega $ for the same accuracy. Multiple variations of the proposed circuit are designed and experimentally tested for verifying the tunability of the circuit in terms of the sensitivity and the range of resistance measurement. The prototype circuit is also interfaced with an in-house fabricated MEMS-based ammonia sensor, proving its efficacy in resistive sensor system development.

13 citations

Proceedings ArticleDOI
09 Jul 2015
TL;DR: Simulation and experimental results have confirmed the theoretical expectations, showing good linearity in wide oscillation frequency range and the sensitivity and operating frequency of the proposed oscillator can be adjusted using passive components.
Abstract: In this paper, we propose a current-mode based solution suitable for triangular/square wave generator using second generation current conveyor The proposed oscillator, which utilizes two second generation current conveyor (CCII) as active elements, three resistors and a capacitor, is based on resistance-capacitance (RC) cell and found to be effective alternate of voltage-mode based oscillators Experimental results were obtained by implementing the proposed circuit using commercially available CCII (AD844) and passive components Simulation and experimental results have confirmed the theoretical expectations, showing good linearity in wide oscillation frequency range The sensitivity and operating frequency of the proposed oscillator can be adjusted using passive components The proposed configuration finds useful applications in wide range capacitive/resistive sensor front end

13 citations


Cited by
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01 Apr 1983

405 citations

Journal ArticleDOI
TL;DR: New approaches in the world of electrochemical sensors that accomplish the main features that clinical POC devices should comply, such as affordability, disposability, sensitivity, selectivity, stability, flexibility, and ease to handle are focused on.
Abstract: Point of care testing (POCT), i.e., medical tests performed wherever the patient is with the possibility to immediately get and send the results to the doctor for clinical decision making, is a social need which nowadays is witnessing rapid growth. Major technological progress, internet, mobile phones available to almost everyone, outstanding developments in the world of sensors, and miniaturization of devices facilitate to make a test without significant medical knowledge, allowing getting the results and the doctor's response in a short time. Electrochemical sensors play a key role in this field due to their ability to be adapted to small devices, whether hand-held or wearable at a low cost. This review focus on new approaches in the world of electrochemical sensors that accomplish the main features that clinical POC devices should comply, such as affordability, disposability, sensitivity, selectivity, stability, flexibility, and ease to handle.

50 citations

Journal ArticleDOI
TL;DR: An analog interface for differential capacitance estimation, able to reveal and quantify capacitive variations, can operate on a full-range scale and is based on a modified De-Sauty AC bridge configuration.
Abstract: The authors here propose an analog interface for differential capacitance estimation, able to reveal and quantify capacitive variations. Different from other works in the literature, the proposed interface can operate on a full-range scale. This solution takes inspiration from a preliminary work of the same authors, whose working principle is based on a modified De-Sauty AC bridge configuration; in particular, two (differential) capacitors and two resistors are employed, one of which is implemented by a voltage-controlled resistor (VCR). In this paper, the electronic interface has been redesigned to obtain full-range operation and a linear input–output characteristic. The implemented autobalancing mechanism controls the VCR generating a reference voltage following the sensor output. Simulation results in two different circuit configurations performed by OrCAD PSpice have shown a very good agreement with a theoretical model implemented in MATLAB/Simulink environment. In addition, an evaluation of the goodness of the experimental measurements at steady and unsteady conditions is given. Experimental tests on a discrete-component prototype have been carried out using an automated test equipment including National Instruments tools and a dedicated software in the LabVIEW environment. Measurements have shown satisfactory results, the standard deviation being on the order of 0.01, in the worst case. The linearity error has been evaluated as well, resulting in lower than 1% full scale.

47 citations

Journal ArticleDOI
TL;DR: The prototype developed has the option to easily adjust the sensitivity and operating range, depending on the application, and is based on the measurement of quadrature and in-phase components of the signal.
Abstract: This paper presents a low-cost interface circuit for lossy capacitive sensors. Most of the capacitive sensors are lossy in nature, where the resistance value of the sensor significantly varies along with the capacitance value. Accurate measurement of those values of a lossy capacitive sensor is a challenging task. This paper deals with the development of an electronic interface circuit for such a capacitive sensor. The circuit is based on the measurement of quadrature and in-phase components of the signal. To extract the actual value of the capacitance and the resistance, an average of the quadrature and the in-phase components of output is required. This is implemented using a microcontroller and provides flexibility in averaging (e.g., adjustable length of data to be processed). A PCB of the circuit has been fabricated and tested in the laboratory using capacitors and resistors with known values. The accuracy of the circuit was better than 0.6% and −2.2% for the measurement of capacitance and resistance, respectively. Also, the circuit is highly linear (FS nonlinearity of 0.32%) for a wide range of capacitance measurement (162 pF–3.680 nF). To confirm the effectiveness of the circuit, it was interfaced to a lossy capacitive humidity sensor and another capacitive transducer to measure the dielectric constants of edible oils. The results were compared with a precision impedance analyzer (Agilent 4294A); the maximum relative error was noted as ±1.6% in the measurement of permittivity values of edible oil. The prototype developed has the option to easily adjust the sensitivity and operating range, depending on the application.

36 citations

Journal ArticleDOI
TL;DR: An integrable novel fully analog Wheatstone bridge-based interface for differential capacitance estimation is presented, which takes advantage of the modified De-Sauty AC bridge configuration being employed only by two capacitors and two resistors.
Abstract: Summary In this paper, an integrable novel fully analog Wheatstone bridge-based interface for differential capacitance estimation is presented. Its working principle takes advantage of the modified De-Sauty AC bridge configuration being employed only by two capacitors and two resistors. A feedback loop controls one of the resistors (e.g. a voltage-controlled resistor), to obtain an evaluation of the differential capacitance variation on a full range, thanks to a general but very simple formula that considers both the ‘auto-balancing’ and the bridge ‘out-of-equilibrium’ ranges. The proposed interface shows a satisfactory accuracy, being the percentage relative error within 0.45% for the experimental results. Copyright © 2016 John Wiley & Sons, Ltd.

36 citations