This paper analyses the electrical response of a quasi-adiabatic, thin-film nanocalorimeter system for the purpose of obtaining values of the heat capacity of ultra-thin samples. The pulse-heating method of heat capacity measurement is based on the observation of the temperature rise during the heating of the sample by a pulse of current. By measuring the voltage and current (in differential mode) of both reference and sample cells of the calorimeter during the pulse, the heat capacity is obtained. Also described are different methods to derive corrections for the baseline to account for the non-ideal differences between the reference and sample cells characteristics, including differences in addendum and resistance-temperature response. Further analysis accounts for the actual heat loss during the measurement, shunting effects of current through the substrate, and heat capacity of the blank calorimeter. Examples of the effects of each of the non-ideal conditions are given. (C) 2003 Elsevier B.V. All rights reserved.