Screen-Printed Dry Electrodes: Basic Characterization and Benchmarking

The electrical performance of screen-printed dry electrodes on thermoplastic polyurethane substrates are evaluated according to their conformance to international standards, skin-electrode impedance, and ability to gather high quality electrocardiograms. The electrical behavior of seven screen-printed electrodes (Ag, Ag/PEDOT:PSS, Ag/AgCl, Ag/AgCl/PEDOT:PSS, C, C/AgCl, and PEDOT:PSS) is compared to two commercially available gel electrodes (3M RedDot 50 and Philips NeoLead) which represent the state-of-the-art. After basic standard electrical characterization (electrode-electrode impedance, direct current [DC] offset voltage, defibrillation recovery, bias stress, and noise), it is shown that layers such as AgCl or PEDOT:PSS help to reduce the contact impedance of dry electrodes. However, the quality of the electrical signal is primarily governed by the skin impedance, which, without physical disruption or preparation, maintains a high impedance. For this reason, the impedance of all screen-printed dry electrodes allows the collection of electrocardiograms with a quality equal to that of gel electrodes. Dry electrodes, while capable of obtaining similar electrical signal quality also bring the advantages of reusability, comfort, and the capability for long-term measurements.