| 摘要 |
PURPOSE:To improve the reliability of photo repeating and also to prolong its lifetime by providing a photo repeater with several converters with incorporated semiconductor components and then by automatically switching and using the repeater when the semiconductor components of a converter in use deteriorates. CONSTITUTION:Electro-photo conversion part 7 is provided with several electro- photo converters 141-14n in parallel, one of which is put into operation by being supplied with a bias current and driving current selected by electric change-over switch 13. Further, deterioration detecting method 18 exercises a supervision over this bias current and when it exceeds a reference value, it detects it to make a decision on deterioration. On receiving the output signal of detecting method 18, control circuit 19 controls driver circuit 20 of switch 13 and driver circuit 21 of photo change-over switch 16. Bias current supply 22 operates photo-electric converter 2 by supplying the bias current. This constitution is unchangeable in case of a plural number of photo-electric converters 2 or a plural number of both converters, so that its reliability will improves while its lifetime is also prolonged equivalently. |
