In the present work the frequency response of the electrochemical interface is investigated during the electrodissolution of copper in trifluoroacetic acid (TFA). The instability of a stable steady state to periodic oscillations is characterized and thus the nature of the steady state close to the instability is revealed to be a stable focus. The frequency response of the stable focus is explored by electrochemical impedance spectroscopy and the impedance amplitude profile (ZAP) method. It is shown that the system resonates at a specific frequency of the input signal and thus acts as a resonator (band-pass filter) similarly to neural resonators. (C) 2010 Elsevier B.V. All rights reserved.