A mathematical model is developed to calculate the impedance response of a semiconductor electrode to a sinusoidal current perturbation. The model accounts explicitly for electron and hole transport as well as generation and recombination through band-to-band mechanisms and through bulk interband electron acceptors of specified energy. The resistive (real) component of the impedance is shown to be sensitive to the concentration, distribution, and energy level of the bulk sites. The capacitive (imaginary) component, while useful for determining the dopant level and the flat-band potential of the semiconductor, is relatively insensitive to low concentrations of bulk sites.