Answer:
The equivalent circuit for the electrode while the electrolyte gel is fresh
From the uploaded diagram the part A is the electrolyte, the part part B is the electrolyte gel when is fresh and the part C is the surface of the skin
Now as the electrolyte gel start to dry out the resistance [tex]R_s[/tex] of the gel begins to increase and this starts to limit the flow of current . Now when the gel is then completely dried out the resistance of the gel [tex]R_s[/tex] then increases to infinity and this in turn cut off flow of current.
The diagram illustrating this is shown on the second uploaded image
Explanation: