| 摘要 |
PURPOSE:To attain to enhance measuring accuracy, by synchronizing an illumination instrument and a data treating circuit only when the output of a power source reaches a definite value or more. CONSTITUTION:A one shot generating circuit 5 generates a pulse at a zero cross time on the basis of the output wave form of a power source 4 for lighting a fluorescent lamp while a delay circuit 6 generates a pulse delayed by a predetermined time from the pulse at the zero cross time and a data treating circuit 7 is controlled by this delay pulse. When an inspection time is determined in the treating circuit 7, the light amount of the fluorescent lamp 3 at the inspection time is brought to only the stable part of the current amount in the central part of a sine wave from showing the output of the power source 4. As mentioned above, when measurement is performed by using only light high in a light amount, signal voltage relatively becomes large with respect to noise voltage due to the dark current of a light emitting element and S/N is enhanced. |
