Figure 5
The figure presents a color-coded equivalent electrical circuit model arranged horizontally from left to right. On the far left, a green rectangular resistor labeled R subscript S (solution resistance) is connected in series to the remainder of the circuit. Immediately after R subscript S, the circuit splits into a large parallel block with two main paths. The upper path contains a capacitor-style element labeled C P E subscript f, representing a constant phase element associated with the film or surface layer. This upper branch runs directly from the left junction to the right output node. The lower path begins with a rectangular resistor labeled R subscript f. After R subscript f, this lower branch splits again into a smaller parallel subnetwork. In the upper part of this subnetwork is a capacitor-style element labeled C P E subscript d l (double-layer constant phase element). In the lower part is another rectangular resistor labeled R subscript c t (charge-transfer resistance). These two components, C P E subscript d l and R subscript c t, are arranged in parallel with each other and reconnect at the right side. The outputs of the upper main branch (C P E subscript f) and the lower main branch (containing R subscript f followed by the C P E subscript d l–R subscript c t parallel pair) join at the rightmost node, completing the circuit.Equivalent circuit used for fitting electrochemical impedance spectra of neutral and alkaline cleaning agents. Source(s): Authors’ own work