Household or commercial appliance comprising: - a heating chamber designed to accommodate a product to be heated, - at least a couple of magnetrons having relative anodes (TA1)(TA2) and cathodes (TC1)(TC2) and being configured to generate and irradiate electromagnetic radiations in the heating chamber , - at least a power unit comprising at least a high voltage circuit configured to power-on said magnetrons , characterized in that said high voltage circuit comprises: - a high voltage transformer comprising a primary winding connected to an alternating voltage source and at least a secondary high-voltage winding providing an alternating high voltage (V2) having a period (W) comprising two half periods (W1)(W2), - at least a couple of half-wave voltage doubler circuits which are configured to cooperate with said secondary high-voltage winding in order to provide a doubled high-voltage (DVH), - at least a first and second unidirectional conducting devices which are connected respectively between said half-wave voltage doubler circuits and a reference terminal having a predetermined potential (GND), said first and second unidirectional conducting devices being configured to cause said half-wave voltage doubler circuits to supply, during at least a period (W) of said alternating high-voltage (V2), said doubled high-voltage (DVH) to the cathode (TC1)(TC2) of the respective magnetron alternately, one of said half-wave voltage doubler circuits supplying said doubled high-voltage (DVH) during one of said half periods (W1) of said alternating high-voltage (V2), and the other half-wave voltage doubler circuit supplying said doubled high-voltage (DVH) during the other half-period (W2) of said alternating voltage (V2). - a heating chamber designed to accommodate a product to be heated, - at least a couple of magnetrons having relative anodes (TA1)(TA2) and cathodes (TC1)(TC2) and being configured to generate and irradiate electromagnetic radiations in the heating chamber , - at least a power unit comprising at least a high voltage circuit configured to power-on said magnetrons , - a high voltage transformer comprising a primary winding connected to an alternating voltage source and at least a secondary high-voltage winding providing an alternating high voltage (V2) having a period (W) comprising two half periods (W1)(W2), - at least a couple of half-wave voltage doubler circuits which are configured to cooperate with said secondary high-voltage winding in order to provide a doubled high-voltage (DVH), - at least a first and second unidirectional conducting devices which are connected respectively between said half-wave voltage doubler circuits and a reference terminal having a predetermined potential (GND), said first and second unidirectional conducting devices being configured to cause said half-wave voltage doubler circuits to supply, during at least a period (W) of said alternating high-voltage (V2), said doubled high-voltage (DVH) to the cathode (TC1)(TC2) of the respective magnetron alternately, one of said half-wave voltage doubler circuits supplying said doubled high-voltage (DVH) during one of said half periods (W1) of said alternating high-voltage (V2), and the other half-wave voltage doubler circuit supplying said doubled high-voltage (DVH) during the other half-period (W2) of said alternating voltage (V2). <EOS>