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I have an AUTOLAB potentiostat: working electrode (WE, Pt wire), counter electrode (CE, Pt wire), reference electrode (RE, Ag/AgCl solid state).

I would like to capacitively couple the potentiostat and the three electrode cell system through the working electrode by connect a capacitor in series with the WE.

Am I doing it right? I read in a paper by van Dongen and Serdijn [1] that capacitive coupling could increase the cell potential during stimulation I would like to do. How should I do it to prevent this increase, or minimize it? Even the OCP is not the same, if I connect the capacitor into the cell.

Reference

  1. van Dongen, M. N.; Serdijn, W. A. Does a Coupling Capacitor Enhance the Charge Balance during Neural Stimulation? An Empirical Study. Med Biol Eng Comput 2016, 54 (1), 93–101. DOI: 10.1007/s11517-015-1312-9.
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    $\begingroup$ Nice linked paper, but perhaps look at my answer here and the figure. It seems you want to insert a capacitor between the working electrode and the op amp’s inverting input. That yields a differentiator configuration: it blocks DC offset voltage, but differentiators are intrinsically noisy. So then you would likely need a somewhat more complicated configuration, e.g., some low pass filtering. So this is really an electronics problem and we have some electrical engineers here. Maybe one will suggest something or post an answer. $\endgroup$
    – Ed V
    Jul 26 at 14:18
  • $\begingroup$ I do not think so, that low pass filter would be efficient in my case as these Pt microelectrodes (WE) will be used for cochlear implants. Could anyone describe what low pass filtering could be of use here, what are the details? $\endgroup$
    – Ryksa
    Jul 27 at 8:18
  • $\begingroup$ A differentiator configuration is a high pass filter, so you get the derivative of the response and you want to roll off the excess high frequencies. Have you considered not altering the front end and simply digitizing the response (with, e.g.,a 16 bit ADC) so you can use software processing (signal processing) to deal with the DC voltage offset? I will not comment further since we have users here who are also high rep in the electrical engineering stack exchange. $\endgroup$
    – Ed V
    Jul 27 at 10:34

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