The behavior of current–voltage characteristics (CVC) within the classical Shockley and Shockley–Noyce–Sah models depending on the nature of the distribution of recombination centers in the space charge region of the p–n junction was analyzed. Notably, the non-ideality factor determined from experimental CVC cannot be introduced into the exponent of the mathematical model of the CVC because it is unrelated to the physical nature of the exponentials of classical models but indicates the voltage dependence of the pre-exponential factor of the recombination component of the total current. The exponential factor of the model with a non-ideality factor describing the experimental CVC presents only a mathematical approximation of a small portion of it.