Proceedings ArticleDOI
An oscillator based active bridge circuit for converting capacitance change into frequency for capacitive humidity sensor
Tarikul Islam,A. Gangopadhyay,Zaheeruddin +2 more
- pp 480-483
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TLDR
The design, analysis, and experimental results of the circuit and its application to a sol gel thin film porous γ-Al2O3 based humidity sensor confirm the theoretical value predicted and have the potential for remotely monitoring measurement parameters accurately.Abstract:
A simple signal conditioning circuit for converting capacitance change into frequency for capacitive humidity sensors is presented. It is based on a relaxation oscillator in which output frequency is linearly related to the capacitive unbalance of an active bridge. The design, analysis, and experimental results of the circuit and its application to a sol gel thin film porous γ-Al 2 O 3 based humidity sensor are reported. Experimental results confirm the theoretical value predicted. The circuit covering wide capacitance measurement range has the potential for remotely monitoring measurement parameters accurately.read more
Citations
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Novel Modified De-Sauty Autobalancing Bridge-Based Analog Interfaces for Wide-Range Capacitive Sensor Applications
TL;DR: In this article, the authors proposed novel fully analog uncalibrated readout circuits for wide-range capacitance estimation based on a modified De-Sauty ac bridge configuration where two capacitances and two resistances are employed.
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Air-filled substrate integrated cavity resonator for humidity sensing
TL;DR: In this article, an air-filled substrate integrated cavity resonator (SIW) is used for humidity detection in a multilayer printed circuit board, which exhibits high sensitivity, repeatability stability and fast response/recovery time.
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An Oscillator-Based Active Bridge Circuit for Interfacing Capacitive Sensors With Microcontroller Compatibility
TL;DR: The circuit is less complex and is easy to integrate to application-specific integrated circuits in a standard CMOS technology with high sensitivity (selectable) and can be easily reproduced with the cheapest possible components, while achieving fairly good performance in terms of both accuracy and dynamic range.
Proceedings ArticleDOI
Accuracy analysis of oscillator-based active bridge circuit for linearly converting resistance to frequency
TL;DR: In this article, a resistance to frequency convertor circuit proposed by the authors is critically analyzed in non-ideal conditions, due to the behavior of real components there is a deviation from idealities.
Proceedings ArticleDOI
A highly sensitive readout circuitry for a wide range thin film capacitive humidity sensors
TL;DR: In this paper, the authors present a highly precise and stable electronic readout circuitry for acquiring and processing raw signal data from capacitive sensors, which can accurately measure the sensor capacitance in real-time and converts to frequency.
References
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A high-resolution, linear resistance-to-frequency converter
K. Mochizuki,Kenzo Watanabe +1 more
TL;DR: In this article, a resistance-to-frequency converter consisting of a Wheatstone bridge followed by an integrator and a comparator is described, whose frequency changes linearly with a resistance change detected by the bridge.
Journal ArticleDOI
A novel sol–gel thin film porous alumina based capacitive sensor for measuring trace moisture in the range of 2.5–25 ppm
TL;DR: In this paper, a low cost moisture sensor for measuring moisture in the range of 2.5-25ppm using nanoporous thin film of alumina (γ-Al 2 O 3 ).
Journal ArticleDOI
Oscillator-based signal conditioning with improved linearity for resistive sensors
TL;DR: A signal conditioning circuit for resistive sensors is presented based on a relaxation oscillator in which both the frequency and the duty-cycle of the square-wave output signal simultaneously carry information from a pair of different sensors.