Abstract: A bidirectional DC-AC inverter is disclosed. The DC-AC inverter includes an H bridge circuit, a connecting portion connected to the H bridge circuit, a smoothing filter that connects the connecting portion to the H bridge circuit, and a control section. The H bridge circuit has four switching elements. The four switching elements include two first switching elements first ends of which are connected to each other and two second switching elements second ends of which are connected to each other. The smoothing filter has a capacitor and two coils connected to the capacitor. The control section controls the first switching elements in such a manner that the two coils function as booster coils when an alternating voltage input from a system power supply is converted to a direct current voltage.

Abstract: A power supply unit that allows a main battery and an auxiliary battery to be charged by a system power supply is disclosed. The first and second bridge circuits of the power supply unit are each formed of four switching elements. The transformer of the power supply unit has a primary winding connected to the first bridge circuit, and a secondary winding connected to the second bridge circuit. The DC/DC converter of the power supply unit allows the auxiliary battery to be connected to the first and second circuits. The controller of the power supply unit controls the switching elements of the first bridge circuit, the switching elements of the second bridge circuit, and the switching element of the DC/DC converter such that power that has been charged to the main battery is output as an AC voltage having voltage and frequency for electric appliances.

Abstract: There is provided a heat sink capable of keeping a heating element at a desired temperature without using a unit other than the heat sink. The heat sink of the present invention includes: closed container 3 covered with heat insulation material 2; heat transfer member 12 constructed of heat transfer part 10, which is brought into contact with heating element 1, and heat transfer fin 5 provided in such a way as to extend from a face on a side opposite to a face that belongs to heat transfer part 10 and at which heat transfer part 10 is brought into contact with heating element 1; heat radiation fin 7 for radiating heat; and heat storage material 4 enclosed in closed container 3.

Abstract: A wafer on which a plurality of semiconductor chips are formed, and the wafer includes a temperature control circuit embedded in the wafer and configured to control its periphery temperature in the wafer to a predetermined target temperature; and a pad to which a start signal is supplied to start the thermal control circuit. The temperature control circuit is started in response to the start signal to automatically perform a temperature control without receiving any control signal.

Abstract: A bidirectional DC-AC inverter is disclosed. The DC-AC inverter includes an H bridge circuit, a connecting portion connected to the H bridge circuit, a smoothing filter that connects the connecting portion to the H bridge circuit, and a control section. The H bridge circuit has four switching elements. The four switching elements include two first switching elements first ends of which are connected to each other and two second switching elements second ends of which are connected to each other. The smoothing filter has a capacitor and two coils connected to the capacitor. The control section controls the first switching elements in such a manner that the two coils function as booster coils when an alternating voltage input from a system power supply is converted to a direct current voltage.

Abstract: A power supply unit that allows a main battery and an auxiliary battery to be charged by a system power supply is disclosed. The first and second bridge circuits of the power supply unit are each formed of four switching elements. The transformer of the power supply unit has a primary winding connected to the first bridge circuit, and a secondary winding connected to the second bridge circuit. The DC/DC converter of the power supply unit allows the auxiliary battery to be connected to the first and second circuits. The controller of the power supply unit controls the switching elements of the first bridge circuit, the switching elements of the second bridge circuit, and the switching element of the DC/DC converter such that power that has been charged to the main battery is output as an AC voltage having voltage and frequency for electric appliances.

Abstract: There is provided a semiconductor device tester including (a) a tester substrate having the same structure as a structure of a substrate as a product except that a semiconductor device is not mounted on the tester substrate, (b) an electrically conductive sheet covering therewith a first area in which the semiconductor device is to be mounted on the tester substrate, the electrically conductive sheet being electrically insulating in a certain direction, and (c) a holder supporting a semiconductor device to be tested therewith, and compressing the semiconductor device onto the electrically conductive sheet to thereby electrically connect an externally projecting terminal of the semiconductor device to a connection terminal mounted on the tester substrate in the first area.

Abstract: In a large-scale integrated circuit, a scan path is divided between an I/O scan path that is formed by a series connection between only flip-flops that are in a region near an I/O pin and an internal scan path that is formed by a series connection between other flip-flops. A selector has one of its inputs connected to another end of the I/O scan path and to one end of the internal scan path, another of its inputs connected to another end of the internal scan path, and its output connected to a scan out. This selector, based on a test mode signal, selects either all scan paths or only the I/O scan path.

Abstract: There is provided a semiconductor device tester including (a) a tester substrate having the same structure as a structure of a substrate as a product except that a semiconductor device is not mounted on the tester substrate, (b) an electrically conductive sheet covering therewith a first area in which the semiconductor device is to be mounted on the tester substrate, the electrically conductive sheet being electrically insulating in a certain direction, and (c) a holder supporting a semiconductor device to be tested therewith, and compressing the semiconductor device onto the electrically conductive sheet to thereby electrically connect an externally projecting terminal of the semiconductor device to a connection terminal mounted on the tester substrate in the first area.

Abstract: A method and an apparatus for preventing a solenoid from being heated by an exciting current. When a hydraulic cylinder is permitted to extend and retract, a controller commands a high-side driver to send a moving current to the solenoid such that a valve body of an electromagnetic valve is moved to a connection position. Subsequently, the controller commands the high side driver to send a maintaining current to the solenoid such that the valve body is maintained at the connection position. The moving current and the maintaining current are pulse waves. The duty ratio of the maintaining current is smaller than that of the moving current.

Abstract: This disclosure relates to a method for producing polyethylene open-cell foam materials, comprising a process step of pressurized heating at a temperature of 110.degree. to 135.degree. C. of a base compound consisting of polyethylene or a copolymer of polyethylene which has been compounded with an azodicarbonamide foaming agent and a bridging agent, in order to obtain a primary intermediate product with a cubical expansion coefficient of 1.0 to 2.0 times; a process step of heating the primary intermediate product under normal atmospheric pressure at a temperature of 150.degree..about.190.degree. C.

Abstract: An open-cell foamed article of a cross-linked polyolefin having a high open-cell ratio and a high degree of expansion is produced by a method which comprises the steps of preparing a foamable and cross-linkable polyolefin composition, forming the composition into a desired shape maintaining its gel percent at zero, decomposing the cross-linking agent and blowing agent concurrently by heating the composition under atmospheric pressure in such conditions that the peak of the ratio of the degree of cross-linking to the degree of decomposition of the blowing agent is not more than 20 and exerting a mechanical deformation to the resulting polyolefin foam to rupture the cell membranes.