Abstract: A temperature control circuit particularly for use with a graphite tube atomizer of an atomic absorption spectrometer provides rapid temperature rise and a leveling at a constant predetermined temperature. A.C. power applied through a transformer to electrodes on the ends of the graphite tube rapidly heats the tube and the visible radiation thus produced is measured by a photocell, the output of which is amplified to control a relay in the graphite tube power circuit. When the desired tube temperature is approached, the photocell output actuates the relay so that the tube power circuit will switch from the high voltage rapid heating mode to a controlled lower voltage that will automatically maintain the constant predetermined tube temperature.