Abstract: An electric supply circuit for a microwave oven provided with a magnetron tube in which an anode circuit is supplied with high tension, the circuit comprising a mains supply, a leak field transformer having a primary winding and a secondary winding, the secondary winding supplying the anode circuit, two parallel branches connecting the primary winding of the transformer to the mains supply, a first one of the two branches including a switch and a protective resistor serially connected, a second one of the two branches including a relay contact, and a relay coil being connected in series to the protective resistor and forming an additional branch which is connected in parallel to the primary winding of the transformer, the relay coil controlling the relay contact, the first one of the branches being closed upon actuation of the switch supplying the relay coil and the primary winding via the protective resistor, the second one of the branches being closed upon exitation of the relay coil to close the relay cont