A simplified two-wired biopotential active electrode topology

GUERRERO, FEDERICO NICOLÁS; CATACORA, VALENTÍN; HABERMAN, MARCELO ALEJANDRO; SPINELLI, ENRIQUE MARIO

Florencio Varela y Buenos Aires

Congreso; XXIV CONGRESO ARGENTINO DE BIOINGENIERÍA (SABI2023); 2023

Sociedad Argentina de Bioingeniería

Active electrodes include electronic devices allowing to present a veryhigh impedance to the biopotential signal that is to be acquired, and at the sametime a very low output impedance, thus achieving robust acquisition systems relative to electromagnetic interference. Their main drawback is that power must befed to the electrode. The most usual solution employs 3 wires for this purpose:two providing the supply voltage, and the third one the output signal. Anotheralternative is the use of only 2 wires. In this latter case, the active electrode is fedthrough a current source and one of the wires has the double function of providingenergy and transmitting the signal. In this work, a circuit which replaces the current source with a simple resistor and that is functional with a single supply ispresented. The circuit is extremely simple requiring a reduced number of components, and one of its wires is ground-connected thus being suitable for use inshielding. The circuit analysis is presented, as well as its design equations andexperimental results through electrocardiographic signal measurements