| 摘要 |
PURPOSE:To execute a quick stabilization by an appropriate charge-up in case when a power source is turned on by a simple constitution by connecting a constant-current source to a circuit in which an output photoelectric current of a semiconductor optical position detector flows, and making a constant bias current flow. CONSTITUTION:A constant-current source CC is connected to a circuit in which an output photoelectric current IL1 of a semiconductor optical position detector PSD2 flows, a constant bias current is made to flow from this constant-current source CC, and a photoelectric current by a stationary light is biased. By making this bias current flow, a difference of the photoelectric current between when the stationary light is bright and when it is dark can be set to a small ratio against when the stationary light is bright, namely, when the photoelectric current is large. In this way, when a charge-up current I and a charge-up pulse width (tw) are constituted so as to conform with the time when the stationary light is bright, the stabilization is executed quickly by a simple constitution.
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