Comparison of the performance of thermally deposited aluminum thin films on etched PCB as a capacitive humidity sensor before and after aging

Abstract

A capacitive humidity-sensing device was created by coating both sides of etched double-sided PCB with aluminum. The device was calibrated by comparing the readings of capacitance of the non-aged device with that of the relative humidity sensor of the Vernier LabQuest2. It was found that there is a linear relationship between the capacitance and relative humidity given by the equation C=1.418RH+29.139 where C is the capacitance and RH is the relative humidity. As the device is aged, it was found that it no longer retained the linear relationship between the capacitance and relative humidity The response of the capacitance was less due to the presence of dust that inhibited the adsorption and capillary condensation of water.