Banco de capacitores com ajuste automático

Abstract

This project aims to develop an electronic device that controls the output capacitance of a square matrix (2x2), whose elements are capacitors. The device is managed by a microcontroller, which associates the capacitive elements, through electromechanical relays, according to the defined capacitance value by the user. Thus, the device functionality is evaluated according to two validation methods. The first one is based on using the capacitor matrix as the capacitive element of an active low-pass first-order filter in order to vary the cutoff frequency. On the other hand, the second method consists of the direct measurement of the equivalent capacitance at its output terminals using a digital LC meter, followed by a comparison with the manual association measurement for the same capacitors. The frequency responses related to the first validation method were similar to the manual association ones. The same behavior has been found for the second method. However, in both validation methods it has presented an error around ± 20% when using the 120 pF capacitors.