Abstract: A problem of the invention is to provide a high frequency heating apparatus capable of realizing excellent heating without an irregularity in heating even for a thick-walled heated object. In order to resolve the above-described problem, according to a high frequency heating apparatus of the invention, a high frequency heating apparatus 1 for heating a heated object by irradiating a microwave having a frequency of 5.8 GHz to the heated object is constituted by mounting a plurality of pieces of wave guides 11a, 11b having feeding ports 7, 9 for emitting microwaves into a cavity 3 partitioning a heating chamber 2.

Abstract: A problem of the invention is to provide a high frequency heating apparatus capable of realizing excellent heating without an irregularity in heating even for a thick-walled heated object. In order to resolve the above-described problem, according to a high frequency heating apparatus of the invention, a high frequency heating apparatus 1 for heating a heated object by irradiating a microwave having a frequency of 5.8 GHz to the heated object is constituted by mounting a plurality of pieces of wave guides 11a, 11b having feeding ports 7, 9 for emitting microwaves into a cavity 3 partitioning a heating chamber 2.

Abstract: It is provided a magnetron drive power supply wherein a series connection body of first and second semiconductor switch elements that can be brought into reverse conduction and a series connection body of first and second diodes are connected in parallel, first and second capacitors are connected in parallel to the first and second diodes, a series circuit of a commercial power supply and a primary winding of a high-voltage transformer is connected between a connection point of the first and second semiconductor switch elements that can be brought into reverse conduction and a connection point of the first and second diodes, and output of a secondary winding of the high-voltage transformer energizes a magnetron through a high-voltage rectification circuit.

Abstract: It is provided a magnetron drive power supply wherein a series connection body of first and second semiconductor switch elements that can be brought into reverse conduction and a series connection body of first and second diodes are connected in parallel, first and second capacitors are connected in parallel to the first and second diodes, a series circuit of a commercial power supply and a primary winding of a high-voltage transformer is connected between a connection point of the first and second semiconductor switch elements that can be brought into reverse conduction and a connection point of the first and second diodes, and output of a secondary winding of the high-voltage transformer energizes a magnetron through a high-voltage rectification circuit.

Abstract: A primary winding (1) and a secondary winding (2) are layered concentrically with a magnetic substance forming a main magnetic circuit (13) and the magnetic resistance of a subordinate magnetic circuit (14) placed between the primary winding (1) and the secondary winding (2) is adjusted, whereby a concentric multilayer winding transformer having an arbitrary coupling coefficient can be provided.

Abstract: A high frequency heating apparatus including a circuit for driving a magnetron. A circuit comprises a leakage transformer, a second capacitor connected in series to primary coil of said leakage transformer, a second switching device connected in parallel with a series circuit of said primary coil and second capacitor, a first capacitor connected in parallel with said second switching device, and a first switching device connected in series to said second switching device. Under a structure of the present invention, the switching device and the leakage transformer, both being the key components of the circuit, may respectively be used in common either on a circuit of 200V-240V commercial power supply or on a circuit of 100V-120V commercial power supply. This enables volume production of the key components, which leads to a benefit of reduced cost of the components as well as the cost of heating apparatus.

Abstract: A microwave heating apparatus includes a magnetron (6) mounted on a top surface of a wave guide (7). A bottom surface of wave guide (7) is inclined towards the bottom of the wave guide opening. A metal plate (9) is provided with a predetermined clearance above the bottom surface of wave guide (7). The microwaves are irradiated from an antenna (10) of magnetron (6) and travel along the bottom surface of wave guide (7). The microwaves are guided to an opening (8) under regulation by a metal plate (9) dispersion, and thus the microwaves reach the opening without suffering from the loss of energy. An object of heating (1) is irradiated directly by the microwaves with an improved heating efficiency.

Abstract: A switching device is employed in a power supply for driving a magnetron with lower withstand voltage and better controllability. A high frequency heating apparatus comprises a power supply, a leakage transformer connected to the power supply, a first switching device connected in series to a primary coil side of the leakage transformer, a first capacitor, a series circuit of a second capacitor and a second switching device, a driving circuit having an oscillator for driving the first switching device and the second switching device, a rectifier connected to a secondary coil side of the leakage transformer, and a magnetron connected to the rectifier. With this configuration, voltage applied to the first switching device can be clamped, and at the same time, the OFF time can be freely adjustable by the effect of the second capacitor and the second semiconductor switching device.

Abstract: A high-frequency heating apparatus comprises an inverter including a semiconductor switch and a resonance capacitor, a boosting transformer for a supplying high-voltage power and heater to a magnetron an inductance device inserted in the heater circuit of the magnetron, and an inverter control unit for controlling the semiconductor switch. The inverter control unit is controlled by a start control at the start time of the inverter so that the conduction time of the semiconductor switch becomes shorter than that under a normal operating condition and the non-conduction time thereof becomes longer than that under a normal operating condition and so that the switching period of the semiconductor switch becomes substantially an integral multiple of a resonance period of the resonance circuit formed by the resonance capacitor, whereby the operating frequency of the inverter at the time of starting thereof becomes substantially equal to its normal operating frequency.

Abstract: A high voltage power source device which comprises an electric power source; a low voltage circuit constituted by an inverter circuit including a semiconductor switching element and a capacitor for converting an electric power from the electric power source into a high frequency electric power; a magnetron; a high voltage transformer for converting the high frequency electric power into a high voltage and supplying the high voltage to the magnetron; and a printed circuit board having an electric wiring system formed thereon for connection with and support thereon of the inverter circuit and a high voltage circuit for the voltage boosted by the high voltage transformer. The printed circuit board has separate areas defined therein, and the low and high voltage circuits are formed respectively on the separate areas of the printed circuit board.

Abstract: A high-frequency heating apparatus comprises a semiconductor power converter which is supplied with electric power from a commercial power supply, a radio wave radiation section which is energized by the semiconductor power converter, a control section which controls the operation of a semiconductor element of the semiconductor power converter, and a start control section which controls the operation of the control section at the start time of the high-frequency heating apparatus. The start control section controls the operation of the control section so that the radio wave output power from the radio wave radiation section at the start time of the high-frequency heating apparatus becomes greater than that in the steady operation state thereof, whereby optimization of the performance and price of the heating apparatus can be realized.

Abstract: A magnetron feeding apparatus includes an inverter circuit for converting DC power into high-frequency power; a high-tension transformer for converting the high-frequency power into high-tension power to be supplied to the magnetron; an output voltage detector for detecting the output voltage of the high-tension transformer; an input current detector for detecting the input current into the inverter circuit; a power controller for controlling the operation of the inverter circuit in response to the output voltage detected by the output voltage detector and the input current detected by the input current detector.

Abstract: A heat cooking apparatus accurately detects minor weight variations of an article of food by detecting the weight of the article of food received on a turntable in synchronization with the position of the turntable or its rotational cycle, so as to control the cooking based on such weight variations.

Abstract: A power supply for a magnetron includes a rectifying circuit, a switching circuit, and a transformer. The rectifying circuit converts an ac-power source signal into a dc-power source signal. The switching circuit converts the dc-power source signal output from the rectifying circuit into a high-frequency signal in accordance with a driving circuit. A transformer connected to the switching circuit converts the high-frequency signal into a high-voltage high-frequency signal for driving the magnetron. The transformer includes a primary winding connected to the switching circuit, a secondary winding connected to the magnetron, a tertiary winding connected to a cathode heater of said magnetron, and a fourth winding connected to the driving circuit. The coupling coefficient between the fourth winding and the second winding is larger than the coupling coefficient between the fourth winding and the primary winding.

Abstract: In a high-frequency heating device for driving a magnetron at a high frequency between 20 and 50 KHz, the magnetron is provided with a plurality of choke coils, each of which consists of a magnetic core having a sectional area between 40 to 70 mm.sup.2 and an electric wire around the magnetic core and having a diameter between 1.2 and 1.6 mm. In such a construction, the magnetron can be driven, using the high frequency with reduced thermal loss of the choke coil and restrained heat generation.

Abstract: The invention detects the weight of an object by detecting the change in electrostatic capacity due to a change in the distance between electrodes caused by deflection of flat plates, by using a pressure sensitive sensor having flat plates composed of two elastic insulators stuck together across a proper gap and extending parallel to one another, with electrodes provided at the confronting sides of the flat plates, and by transferring the load of the object to be measured to the sensor through a load support. The gap between the electrodes of this pressure sensitive sensor is enclosed, and a hole is provided to allow air to pass into and out of the gap. Furthermore, the surface of the pressure sensitive sensor is coated with a water-repellent substance to eliminate current loss due to dust or dew deposited on the surface of the electrodes. As a result, the weight may be measured accurately without being effected by temperature changes or humidity.

Abstract: A power feeding apparatus which is used in a high-frequency heater or the like, is further power-converted by a transformer after the power provided by the power supply such as commercial power supply or the like has been converted into the high-frequency power by a transducer including a semiconductor, feeds the converted power into the load having the unidirectional electrical current characteristics of magnetron or the like. The generating voltage is dropped so that the stable power may be fed without the corona discharge and the acr discharge to be caused, the insulating withstand voltage between the windings of the transformer, the pulling of the wirings, and the insulating withstand voltage may be reduced.