Analysis of a Method for Measuring Deposit Impedance Parameters Using Charge Amplifier and Lock-in Voltmeter

Dariusz Robert Wiśniewski

Uniwersytet Warmińsko-Mazurski


Methods for measuring deposit parameters are often based on a capacitance or conductivity measurement aimed at estimating, e.g. deposit moisture content. In practice, these methods fail for materials with a low degree of homogeneity, a diverse porous structure or high conductivity, e.g. due to a high water content. This article demonstrates an approach that enables a more precise estimation of the parameters of any deposit. The presented method involves the use of a measuring system in a charge amplifier configuration and the application of a technique using lock-in detection or a lock-in voltmeter to determine resistance and capacitance parameters of a deposit based on signals received from the measuring system. This method can be successfully used wherever the test deposit material is highly heterogeneous and contains both dielectric and conductive materials. The article presents an example of a solution to a measuring system using two planar electrodes that can be dimensioned depending on the deposit dimensions. It is followed by a presentation of a method for converting the signal from the measuring system into impedance parameters of the deposit using a lock-in voltmeter. The analysis of the operation of the entire measuring system was modelled in Matlab/Simulink, and the operation results were presented.


impedance, conductivity, moisture content, deposit, charge amplifier, lock-in volt- meter

AMBIKA M., MANIKANDAN K., PADMANABAN R. 2019. Design and Fabrication of Electrical Capacitance Tomography Sensor with Signal Conditioning. Biomed Research Journal BMRJ, 3(2): 79-85.   Google Scholar

BAXTER L. 1997. Capacitive Sensors. Design and Applications. IEEE Press Series on Electronics Technology. Robert J. Herrick, Series Editor.   Google Scholar

Characteristic and use charge amplifier. 2001. Technical information SD-37. Hamamatsu.   Google Scholar

FUCHS A., ZANGL H., HOLLER G. 2008. Capacitance-Based Sensing of Material Moisture in Bulk Solids: Applications and Restrictions. Lecture Notes in Electrical Engineering, 20: 235-248.   Google Scholar

KHOSHBAKHT M., LIN M. 2006. Development of an electrical time domain reflectometry (ETDR) distributed moisture measurement technique for porous media. Measurement Science and Technology, 17(11): 2989.   Google Scholar

KRASZEWSKI A., TRABELSI S., NELSON S. 1999. Moisture content determination in grain by measuring microwave parameters. Measurement Science and Technology, 8(8): 857. DOI:10.1088/0957-0233/8/8/004.   Google Scholar

MAURICE A., SHIPLEY B. 2012. Non-destructive estimation of root mass using electrical capacitance on ten herbaceous species. Plant and Soil, 355(1-2): 41-49. DOI:10.1007/s11104-011-1077-3.   Google Scholar

ROFFE J. 1997. A high-sensitivity flexible – excitation electrical capacitance tomography system. Institute of Science and Technology, Manchester.   Google Scholar

SAIED I., MERIBOUT M. 2016. Electronic hardware design of electrical capacitance tomography systems. In: Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences. Royal Society. DOI:   Google Scholar

SMOLIK W., KRYSZYN J., OLSZEWSKI T., SZABATIN R. 2017. Methods of small capacitance measurement in electrical capacitance tomography. Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska, 7(1): 105-110.   Google Scholar

TAN Y., MIAO Z., ABDUL M., GRIFT T., TING K. 2017. Electrical capacitance as a proxy measurement of miscanthus bulk density, and the influence of moisture content and particle size. Computers and Electronics in Agriculture, 134: 102–108.   Google Scholar

TOMKIEWICZ D. 2009. Budowa i działanie czujnika wilgotności ziarna zboża wykorzystującego promieniowanie w zakresie bliskiej podczerwieni. Inżynieria Rolnicza, 6(115).   Google Scholar

WEGLEITER H. 2006. Low-Z Carrier Frequency Front-End for Electrical Capacitance Tomography Applications. Dissertation. Graz University of Technology, Austria.   Google Scholar

WOBSCHALL D., LAKSHMANAN D. 2005. Wireless soil moisture sensor based on fringing capacitance. Proc. of IEEE Sensors, p. 8–11.   Google Scholar

WYPYCH P. 2001. Dilute-phase pneumatic conveying problems and solutions. In: Handbook of Conveying and Handling of Particulate Solids. Eds. A. Levy, H. Kalman. Elsevier Science, Amsterdam, p. 303–318.   Google Scholar

YANG W.Q. 1996. Hardware design of electrical capacitance tomography systems. Meas. Sci. Technol., 7: 225–232.   Google Scholar

YANG W.Q., STOTT A.L., BECK M.S., XIE C.G. 1995. Development of capacitance tomographic imaging systems for oil pipeline measurements. Rev. Sci. Instrum., 66: 4326–4332.   Google Scholar

YANG W.Q., YORK T.A. 1999. New AC – based capacitance tomography system. IEE Proc-Sci. Measurement Technology, 146(1): 47–53.   Google Scholar



Cited by

Wiśniewski, D. R. (2021). Analysis of a Method for Measuring Deposit Impedance Parameters Using Charge Amplifier and Lock-in Voltmeter. Technical Sciences, 24(1), 67–81.

Dariusz Robert Wiśniewski 
Uniwersytet Warmińsko-Mazurski


Copyright (c) 2021 Dariusz Robert Wiśniewski

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.