Abstract: A flow control valve having a seating surface formed on a valve element to contact a valve seat when the valve is closed has a shape of a part of a hypothetical spherical surface having a spherical center at a center of a supporting member. Therefore, the distance from the center of the supporting member to the seating surface is kept constant, and the valve element can be seated at a periphery of the valve seat without a gap, even if the shaft is inclined. Thus, the valve leakage is reduced. The supporting member supports a shaft connected to the valve element movable in an axial direction of the shaft. The center of the supporting member is aligned with a center of the valve seat. Movement of the supporting member in a radial direction of the supporting member is prohibited. Therefore, the center of the supporting member is not displaced from the center of the valve seat in the radial direction. Accordingly, the displacement of the shaft in the radial direction can be prevented.

Abstract: A voltage-driven power semiconductor device includes a voltage-driven IEGT chip, a collector electrode plate, an emitter electrode plate, and an inductance material. The collector electrode plate is connected to the collector of the IEGT chip, and press-contacts the IEGT chip from its collector side. The emitter electrode plate press-contacts the IEGT chip from its emitter side. The inductance material has an inductance component and connects the emitter of the IEGT chip and the emitter electrode plate. In the voltage-driven power semiconductor device having this arrangement, an induced electromotive force is generated in the inductance material arranged between the emitter of the IEGT chip and the emitter electrode plate. This induced electromotive force can suppress a steep current change (di/dt) upon an OFF operation, and can further suppress a steep voltage change (dv/dt) caused by the current change (di/dt).

Abstract: A flow control valve having a seating surface formed on a valve element to contact a valve seat when the valve is closed has a shape of a part of a hypothetical spherical surface having a spherical center at a center of a supporting member. Therefore, the distance from the center of the supporting member to the seating surface is kept constant, and the valve element can be seated at a periphery of the valve seat without a gap, even if the shaft is inclined. Thus, the valve leakage is reduced. The supporting member supports a shaft connected to the valve element movable in an axial direction of the shaft. The center of the supporting member is aligned with a center of the valve seat. Movement of the supporting member in a radial direction of the supporting member is prohibited. Therefore, the center of the supporting member is not displaced from the center of the valve seat in the radial direction. Accordingly, the displacement of the shaft in the radial direction can be prevented.

Abstract: A method of manufacturing power semiconductor device, having an area of 3 cm.sup.2 or more, comprises the step of preparing a power semiconductor device divided into cell blocks and forming power semiconductor elements whose minimum linewidth is less than 10 .mu.m and having at least main electrodes completed in the cell blocks, the step of determining cell blocks having faulty portions, and the step of selectively electrically separating the main electrodes in the faulty cell blocks from the main electrodes in the good cell blocks.