Hardware imitation of the varying bioelectrical impedance for testing the device for measurement of the impedance of human trunk by using a JFET

Abstract

In this paper an approach of imitating the periodically varying electrical bioimpedance of human trunk in case of breathing by using a field effect transistor is presented. The principles of creating a simulation model and preparing a prototype of electronic measurement device, are described. The experiments are presented and the results are compared concerning the change of channel resistance of the field effect transistor and change of real part of impedance of trunk, caused by breathing. The problems of high frequency capacitive measurements and the impact on the design of electronic measurement device are discussed. The results are showing the possibility of using a field effect transistor for imitating breathing. This is a most suitable way of simulation because of the relatively high operating frequency of impedance measurement device needed in the case of using the capacitive electrodes.