A ventilator (1) to be connected to the airways of a human or an animal comprises several functional units, where each functional unit is controlled and/or supervised by a separate microprocessor. At least one of the functional units comprises an analog control unit (11), whereby the microprocessor only compensates for the coarseness in the regulating function of the analog control unit (11) to increase the accuracy. This makes the ventilator (1) expeditious, accurate and safe. <IMAGE>
