Abstract: A semiconductor device includes an intermediate layer provided between a semiconductor element and a heat sink. The intermediate layer moderates thermal stress resulting from a difference between thermal expansion of the semiconductor element and thermal expansion of the heat sink arising due to heat produced by the semiconductor element. This thermal stress moderation reduces warping of the semiconductor device as a whole.

Abstract: A semiconductor device includes an intermediate layer provided between a semiconductor element and a heat sink. The intermediate layer moderates thermal stress resulting from a difference between thermal expansion of the semiconductor element and thermal expansion of the heat sink arising due to heat produced by the semiconductor element. This thermal stress moderation reduces warping of the semiconductor device as a whole.

Abstract: A rotary position detector comprising a rotor rotatable in synchronism with a motor and a rotary position detecting portion for generating a voltage signal corresponding to an angular position detectable as a magnetic flux change with rotation of the rotor. The detecting portion is disposed with respect to the rotor within a range of an angle of 2 &pgr;/n, where &pgr; is the electrical phase angle (180°) and n is the number of pairs of poles of the motor. Further, a motor provided with the same rotary position detector has a motor drive control circuit assembled together with the detecting portion at the same place on the motor. The rotary position detector is easy to manufacture, small and light, easy to mount on a motor and easy to connect with a motor drive control printed circuit.

Abstract: An apparatus for inspecting an electric component in an inverter circuit has a DC power supply for supplying a direct current to a given position in an inverter circuit, a voltage detector for detecting a voltage at a given position in the inverter circuit, a current detector for detecting a current flowing at a given position in the inverter circuit, a switching circuit for changing positions at which the direct current is supplied from the DC power supply, positions at which the voltage is detected by the voltage detector, and positions at which the current is detected by the current detector, and a controller for outputting a switching signal to the switching circuit. The switching circuit is controlled by the controller to charge an electrolytic capacitor in an inverter circuit with a current from the DC power supply. The electrolytic capacitor is determined as to its quality by determining whether the calculated electrolytic capacitance of the electrolytic capacitor falls within a preset range or not.

Abstract: A method and apparatus for inspecting a transistor in an inverter circuit includes turning on only the transistor of the inverter circuit. A predetermined collector current is supplied to the transistor until a transistor junction temperature reaches a predetermined temperature. The transistor is acceptable if a difference between a transistor collector-to-emitter voltage when the predetermined collector current is supplied and a transistor collector-to-emitter voltage when the junction temperature reaches the predetermined temperature falls within a preset range. Switching elements of the inverter circuit are controlled to supply a current through a resistor to charge an electrolytic capacitor of the inverter circuit. A voltage across the electrolytic capacitor during charging and a time period is measured from the beginning of charging until a time when a voltage across the electrolytic capacitor attains a predetermined voltage.

Abstract: An apparatus for inspecting an electric component in an inverter circuit has a DC power supply for supplying a direct current to a given position in an inverter circuit, a voltage detector for detecting a voltage at a given position in the inverter circuit, a current detector for detecting a current flowing at a given position in the inverter circuit, a switching circuit for changing positions at which the direct current is supplied from the DC power supply, positions at which the voltage is detected by the voltage detector, and positions at which the current is detected by the current detector, and a controller for outputting a switching signal to the switching circuit. The switching circuit is controlled by the controller to charge an electrolytic capacitor in an inverter circuit with a current from the DC power supply. The electrolytic capacitor is determined as to its quality by determining whether the calculated electrolytic capacitance of the electrolytic capacitor falls within a preset range or not.