| 摘要 |
PURPOSE:To accurately convert object light into an electric signal by a single photodiode by connecting a switching means in series with the photodiode which has a capacity component and providing a terminal voltage detecting means for the capacity of the photodiode. CONSTITUTION:When the output voltage VOUT at the output terminal P12 of an inverter array 12 is at H level, the potential at the input terminal P11 of the inverter array 12 is almost a source voltage VCC. The junction capacity that the photodiode 1 has is charged to the source voltage VCC. When the delay time td of the inverter array 12 is elapsed after the input terminal P11 rises up to the source voltage VCC, the potential at an output terminal P12 falls to L level because the inverter array 12 is formed of an odd number of inverters 12a-12n. The diode 13 of the switching means is biased reversely, so no current flows from the output terminal P12 to the input terminal P11. |
