A Picofarad Capacitance Meter Based on Phase-Sensitive Demodulation for Tomography Application

https://doi.org/10.22146/juliet.v4i2.89134

Rocky Alfanz(1), Hamzah Hamzah(2), Teguh Firmansyah(3), Irma Saraswati(4), Ceri Ahendyarti(5), Rohmadi Rohmadi(6), Imamul Muttakin(7*)

(1) Universitas Sultan Ageng Tirtayasa
(2) Universitas Sultan Ageng Tirtayasa
(3) Universitas Sultan Ageng Tirtayasa
(4) Universitas Sultan Ageng Tirtayasa
(5) Universitas Sultan Ageng Tirtayasa
(6) Universitas Wiralodra
(7) Universitas Sultan Ageng Tirtayasa
(*) Corresponding Author

Abstract


Electrical capacitance volume tomography (ECVT) is an imaging technique based on the object’s capacitance value. To provide a representative image of the object under study, the ECVT system requires a method that can measure the capacitance value in the order of picofarads (pF). This level of resolution poses a difficulty for typical commercial capacitance measuring devices, hence raising the need for a specialized method with dedicated signal conditioning circuitry. The capacitance meter based on phase-sensitive demodulation (PSD) is made to solve the aforementioned issue and it is then compared with the characteristics of a capacitance meter-based commercial Arduino setup. The designed PSD-based capacitance measuring device has 97.894% accuracy, precision of 0.704 pF, sensitivity of 0.1197 V/pF, linearity with a coefficient of determination 0.9983, and stability of 0.028 pF/min. In comparison, the capacitance meter based on Arduino has 97.943% accuracy, precision of 0.027 pF, linearity with a coefficient of determination 0.9999, and stability of 0.04 pF/min. Testing is done on an 8-electrode ECVT sensor using dielectric materials of air and water. The nearest electrode pair on the condition of air as the dielectric medium has a capacitance value of 2.62218 pF for PSD-based measuring devices and 3.4027 pF for Arduino-based measuring devices, while the pair of electrodes on the condition of water as a dielectric medium has a capacitance value 9.8229 pF for measuring device based on PSD and 9.1069 pF for Arduino-based measuring devices. The opposite and farthest electrode pair on the condition of air as a dielectric medium has a capacitance value of 0 pF for PSD-based measuring devices and 0,0798pF for Arduino-based measuring devices, while the pair of electrodes on the condition of water as a dielectric medium has a capacitance value of 4.652 pF for PSD-based measuring devices and 0.1224 pF for Arduino-based measuring devices.

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DOI: https://doi.org/10.22146/juliet.v4i2.89134

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SINTA 4 accredited based on Decree of the Minister of Research, Technology and Higher Education, Republic of Indonesia Number 225/E/KPT/2022, Vol. 2 No. 1 (2020) - Vol. 6 No. 1 (2025)

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