Design of capacitance measurement circuit for data acquisition system ECVT

In this research, we proposed a capacitance measurement circuit Electrical Capacitance Volume Tomography (ECVT) to perform three-dimensional image visualization. The ECVT system is consists of three main parts i.e. sensor, data acquisition system, and computer. Data acquisition system is composed of capacitance measurement circuit and microcontroller to measure an unknown capacitance inside the sensor, collect data and send it to the computer. Further, these data is used to reconstruct 3D image. The design of the circuit used a sine wave 14.6 V_p-p and 2.5 MHz of frequency injected to the electrode pair to measure an unknown capacitance inside the sensor. An experiment is performed using simulated phantom using sensor having the form of a half-sphere with combined triangular and rectangular shapes. The system is able to measure a capacitance value as low as four femto-Farads with 0.34% margin error.