The importance of using four-terminal sensing for EIS measurements on low-impedance systems

Main Document

Electrochemical impedance spectroscopy (EIS) is used to study all types of electrochemical systems. The internal impedance of the device under test (DUT) can be very small (i.e. a commercial battery), or very high (i.e. a metal substrate with a non-conductive coating). This application note describes the implications of connecting the DUT in a two terminal, versus four terminal, configuration, and shows how the impedance of the cell cables may interfere with EIS measurements on low-impedance DUTs.