If temperature sensors with unusual shapes and dimensions are to be checked, the use of calibration liquids offers advantages. The DUT is placed directly into the liquid without insulating air gaps, thus creating a direct temperature seal between the calibrator and the DUT. The liquid, e.g. silicone oil, is selected according to the required calibration temperature. The continuously variable control of the magnetic stirrer, together with the pull-out sensor basket, causes vortices in the calibration liquid and thus creates a large homogenous temperature zone. Furthermore, the sensor basket ensures an unobstructed stirring operation and serves to protect the tank bottom.