Electrical System for Bioelectric Impedance using AD5933 Impedance Converter

Abstract

Benchtop lab equipment, such as the HP4194A Precision Impedance Analyzer, offer accuracy and functionality but are often expensive and bulky. Although integrated circuits offer less functionality than benchtop equivalents, they can be a cheaper alternative for smaller applications. In this study, the AD5933 Impedance Converter was investigated as a low-cost option for impedance analysis of the bicep brachii. The AD5933 evaluation board was properly calibrated to measure human muscle by using an equivalent parallel circuit consisting of a 5 nF capacitor and a 1 kOhm resistor. Next, the impedance of the bicep was measured using the AD5933 as the experimental device and the HP4194A as the control device. A 2 volt peak-to- peak signal was generated for a 10 kHz to 100 kHz frequency range and the resulting impedance of the bicep was measured. The AD5933 recorded impedance curves qualitatively and quantitatively similar to those recorded by the HP4194A. Thus, the AD5933 was considered to be a low- cost alternative for impedance analysis in small-scale medical applications.