Patent ID: 7550976

Claim:
A measurement apparatus for measuring at least one of the switching times of output signals output from a device under test of high voltage resistant type, the switching times representing the quality of the device under test, said measurement apparatus comprising: a first light-emitting unit having a function whereby, in a ease that the voltage of the output signal becomes equal to or greater than a first threshold voltage, light is emitted; a second light-emitting unit having a function whereby, in a ease that the voltage of the output signal becomes equal to or greater than a second threshold voltage that is higher than the first threshold voltage, light is emitted; a first light reception unit which receives light emitted from said first light-emitting unit; a second light reception unit which receives light emitted from said second light-emitting unit; and a measurement unit which measures the switching time required for the voltage to switch between the first threshold voltage and the second threshold voltage, based upon at least one of the difference in the light-emission start timing and the difference in the light-emission stop timing between said first light-emitting unit and said second light-emitting unit, wherein the first light-emitting unit and the second light-emitting unit are electrically coupled to an output terminal of the device under test.