Can I use medical ear clips to replace Earclip Electrode?

profeellprofeell
in Electrodes

The Earclip Electrode I bought from you last time is broken again. I want to ask, I have found many medical ear clip electrodes on the Internet, can they replace the Earclip Electrode? Can you recommend me other products that can replace it? In addition, what is the impedance parameter of this Earclip Electrode?

Comments

  • wjcroftwjcroft Mount Shasta, CA
    edited June 2025

    There are a wide variety of EEG earclip electrodes available via search:

    https://www.google.com/search?q=eeg+earclip+electrodes

    Most of these will work. However note it may depend on the type electrodes you are using on the scalp.

    'Mixing' electrode metal-types can cause 'galvanic' battery-like effects -- if you are using wet electrodes. For example using gel or paste or saline pads is considered 'wet'. And using for example gold electrodes and silver, or silver and tin, would potentially cause such DC offsets. Those can be quite large battery effects,

    https://www.google.com/search?q=battery+voltage+using+silver+and+tin+and+electrolyte?

    Using silver and tin as electrodes in an electrochemical cell, with an appropriate electrolyte, you can generate a voltage based on the difference in their standard electrode potentials.

    Theoretical Voltage:

    • The standard reduction potential for silver (Ag⁺/Ag) is approximately +0.80 V.
    • The standard reduction potential for tin (Sn²⁺/Sn) is approximately -0.14 V.
    • The theoretical cell potential (E°cell) is calculated by subtracting the standard reduction potential of the anode (oxidation) from the standard reduction potential of the cathode (reduction): E°cell = E°cathode - E°anode.
    • In this case, silver will act as the cathode (reduction), and tin will act as the anode (oxidation), as silver has a higher reduction potential than tin.
    • Therefore, the theoretical voltage is: E°cell = (+0.80 V) - (-0.14 V) = +0.94 V.

    Silver chloride electrodes might be an exception when wet, as these are not technically metal alone. Those are typically plastic base, plated with silver, and 'chlorided'. OpenBCI ear clips are silver chloride based.

    This page from FRI shows similar silver chloride based, with the advantage that the disks can be replaced.

    https://www.fri-fl-shop.com/collections/ear-clip-electrodes

    Other ear clips you would want to avoid are the type used in TENS stimulation. These use rubber tips, but questionable impedance / resistance.

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