| 摘要 |
PURPOSE:To apply the titled circuit also to the high speed optical communication by connecting a photodiode and a saturated resistive element in series, and connecting the gate of a FET to the common connecting point. CONSTITUTION:The photodiode 1 and the saturated resistive element 2 are connected in series and its connecting point 4 is connected to the gate of the FET 3. Thus, the saturated resistive element 2 acts like a current source. Thus, when a light is radiated to the photodiode 1, the resistive element acts like a constant current source and a large voltage is applied to the gate of the FET 3. When no light is radiated, since only a small current flows, the saturated resistive element 2 acts like the nonsaturated region and only a small voltage is applied to the gate of the FET 3 and the electric charge stored in the gate capacitance of the FET 3 is discharged at a high speed forcibly via the resistive element 2.
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