Certain aspects of the blocking layer behavior in semiconductor heterojunction lasers can be modeled as a thin resistive film overlaying a semiconductor forward biased junction. The dc behavior of such a model has been studied previously by W. B. Joyce and S. H. Wemple [J. Appl. Phys.41, 3818 (1970)]. This paper studies the ac aspects of that model, and also makes some of the dc results of Joyce and Wemple more immediately accessible. ©1995 American Institute of Physics.