Measure of the capacitance coefficients of square electrodes using capacitance-to-digital converters

We measure the coefficients of self capacitance C11 and of interelectrode capacitance C12 of a pair of square parallel plates, by using commercial models of capacitance to digital converters. The measured coefficient depends on which charge is sampled, that of the excited electrode or that of the other one. The analysis of the data at large distances is in agreement with the asymptotic formulas for the capacitance coefficients. The different leading behaviour as a function of the distance gives coherent independent estimations of the intrinsic capacitance of a single plate, in good agreement with the calculated one.