Analysis of INA219 Sensor Accuracy and Precision for Current Measurement in a Wheatstone Bridge Circuit

Abstract

This study aims to analyze the accuracy and precision of the INA219 sensor for current measurement in an Arduino Uno-based Wheatstone bridge circuit. The circuit used a 100 cm nickel-chromium wire, a comparison resistor (Rb) of 100 Ω, and three unknown resistance values (Rx) of 100 Ω, 220 Ω, and 470 Ω, with a 5 V power supply. The measurement performance of the INA219 was evaluated through characterization, accuracy, and precision tests. The accuracy test using Rx2 = 220 Ω showed an average error of 0.782% and an average accuracy of 99.218%, with a maximum error of 2.564%. The precision test using Rx3 = 470 Ω at L1 = 40 cm produced an average current of 10.45 mA and a precision of 99.84%. These results indicate that the INA219 provides accurate and consistent current measurements in the tested Wheatstone bridge circuit. However, the relative measurement error increased at low current values, which should be considered when the sensor is used near the bridge balance condition.