Biopotentials and Electrodes (20 points) a. Explain why an electrolyte is needed in the recording of a biosignal. (5 points) b. Provide a circuit schematic representing the electrode and electrolyte interaction. Label each component. Derive an expression for equivalent impedance. Show all work. (5 points) c. Often, after prolonged use, the electrolyte gel begins to dry out and change the characteristic of the electrodes. Discuss how the equivalent impedance will change as the electrolyte gel dries out. In the extreme case where there is no electrolyte gel left, what does the equivalent circuit of the electrode look like? (5 points) d. After some time, you notice the electrode becomes dull and voltage readings drop. You wipe the electrode with steel wool and reapply the electrolyte. What affect do you anticipate this will have on your readings? (5 points)