Abstract: A differential microcalorimeter comprises a means for programmed heating of cells which accommodate heating and thermosensitive elements, a means for measuring power output of a thermal process under study, an a-c voltage source and a temperature measuring circuit, as well as a variable resistor for adjusting the baseline. The outputs of the means for measuring power output of a thermal process under study and of the means for programmed heating of the cells are connected, via appropriate phase-sensitive switches, to the second terminals of the series connected heating elements having their interconnected first terminals connected, via an appropriate phase-sensitive switch, to a movable terminal of the variable resistor for adjusting the baseline.