It has been demonstrated recently that the power response of a polymer electrolyte fuel cell can be interpreted on the basis of a quadratic logistic differential equation. As this is a conceptual approach, the power response was obtained in this work from structural models in order to compare the results with the logistic equation. In this way it is possible to evaluate the contribution of the different effects that limit the response of the cell. It was found that the best comparison between the logistic equation and the structural model is obtained when the dependence of the membrane resistance with current density is considered.