| 摘要 |
<P>PROBLEM TO BE SOLVED: To receive an optical signal and output an optional electric signal according to the presence or absence of power supply. <P>SOLUTION: A light receiving module PD generates an electric signal according to an optical signal. An amplifier AMP amplifies the electric signal by power supply and outputs it to an output terminal J1. A switch element SW1 is open when the power is supplied, and it is short-circuited when no power is supplied. The output terminal J2 is connected with the light receiving module PD through the switch element SW1 and a transformer T1. When the power is supplied to the light receiving module PD, DC current is applied thereto, and a resistance element R2 that can detect a current value of DC current is connected with the switch element SW2 that is short-circuited when the power is supplied and is open when the power is not supplied. The switch element SW2 allows the resistance element R2 to be short-circuited in an alternate current manner when the power is supplied. <P>COPYRIGHT: (C)2010,JPO&INPIT |
