An analytical study of the operation of electret transducers subject to relative displacements of the electrodes comparable to the thickness of the air gap (or air gaps) between electret and electrodes is presented. In particular, the relations between generated voltage and time history of the transducer capacitance are derived for transducers terminated by a combination of resistive and capacitive components. Following this analysis, graphical and numerical results for the shape and peak amplitude of the voltage response due to displacements with trapezoidal time dependence are presented.