The impedance test can't reduce the impedance on certain leads.

winterrrrwinterrrr
in Cyton

During impedance testing, the impedance values of certain leads remain around 3 or 4kΩ. Whether we try to wipe the scalp with an alcohol swab, add conductive paste and put on a net cap to ensure a fit, their impedance values remain unchanged. Moreover, there are two other points I don't understand. Firstly, this stubborn bad sector is not fixed on a single channel. Secondly, I tried to swap the positions of two different channels at the conversion port. For instance, I originally connected channel 7 to the p3 region and channel 8 to the p4 region. At the beginning of the impedance test, the value of channel 7 remained at 4kΩ, but I swapped their positions at the conversion port. Connect Channel 7 to p4 and channel 8 to p3. Then remeasure the impedance. Channel 7 is still 4kΩ. Shouldn't it be channel 8 that becomes 4kΩ? I hope someone can answer this question or teach me some effective methods to reduce my resistance. I would be extremely grateful!

Comments

  • wjcroftwjcroft Mount Shasta, CA

    Hi Winter,

    What electrodes / cap are you using? Is this an OpenBCI cap, cup electrodes or some other?

    @winterrrr said:
    During impedance testing, the impedance values of certain leads remain around 3 or 4kΩ.

    I looked at your screen shot. The electrode impedances in red are actually in the 4 MEGohm range, not kilo-ohms. You should be able to do much better with either cups/paste or a gel cap. It is possible the electrodes are damaged.

    Whether we try to wipe the scalp with an alcohol swab, add conductive paste and put on a net cap to ensure a fit, their impedance values remain unchanged.

    Don't understand your reference to 'net cap'.

    Moreover, there are two other points I don't understand. Firstly, this stubborn bad sector is not fixed on a single channel. Secondly, I tried to swap the positions of two different channels at the conversion port. For instance, I originally connected channel 7 to the p3 region and channel 8 to the p4 region. At the beginning of the impedance test, the value of channel 7 remained at 4kΩ, but I swapped their positions at the conversion port. Connect Channel 7 to p4 and channel 8 to p3. Then remeasure the impedance. Channel 7 is still 4kΩ. Shouldn't it be channel 8 that becomes 4kΩ? I hope someone can answer this question or teach me some effective methods to reduce my resistance. I would be extremely grateful!

    It is remotely possible that you have a bad touchproof adapter cable or bad electrodes or cables or connectors. In all cases you need to ensure the scalp hair is not blocking good connection between skin and electrolyte and electrode.

    https://openbci.com/forum/index.php?p=/discussion/176/placing-electrode-sensors-on-the-scalp

    If you have a resistance meter there (DVM digital voltmeter), you can measure resistance across two points (in your cables or electrodes) to try to narrow down the location of the high impedance.

    William

Sign In or Register to comment.

© Vanilla Keystone Theme 2026