Cooking appliance (1A,1B) having an external and control panel (2,2′) equipped with one or more regulating valves, where the rotary regulator organ (6) is equipped with various peripheral openings (16-19) for supplying a flow Q. According to two embodiments (1A, 1B) of the cooking appliance, for the supply of one or another type of gas, NG or LPG, either the control knob (9) or a bezel disk (22) in the external panel (2) are interchangeable on the appliance, being chosen between two different available units, one and the other permitting two different angular position limits A2, A3 of the regulator organ (6) for the supply of a constant flow Qmin through one or another opening (18,19) with calibrated sections, respectively for NG or LP gas. An appendix (14) in the control knob (9) guided in a slide groove (20) on the control panel (2) of the appliance, or a tongue (24) on the bezel disk stopping the rotation of the control knob, determines the travel limit A2 for the supply of Qmin of NG.