Expressions for the ohmic lines in the IV characteristic for one-dimensional in-line geometry Josephson junctions as well as for two-dimensional cylindrical Josephson junctions are presented. The expressions are compared to numerical simulations of Josephson junctions using the fluxon model; the ohmic line in this model corresponds to a continuous generation at the boundaries of fluxons and antifluxons, being pairwise annihilated in the middle (due to damping). For large currents the results fit to the expressions. Further we find that the fluxon generation in most cases were simply periodic; however, depending on the initial conditions we find 1/2 and 1/3 harmonic generation. Journal of Applied Physics is copyrighted by The American Institute of Physics.