| 摘要 |
PURPOSE:To precisely inform the exchanging time of a laser diode by providing a control circuit with a life establishing circuit wherein the deterioration and the life of the laser diode are indicated by the electric potential of the emitter or collector of a Tr in the control circuit. CONSTITUTION:The output in a laser diode LD is fed back and applied to an output stabilizing circuit 1 through a light sensitive element PD and the output in the laser diode LD is constantly maintained by adjusting the base electric potential VBE in a transistor Q1. The current if flowed into the laser diode LD is informed to an external life establishing circuit 3 by voltage VE or VL. With the value of the if increasing, VE is increased and a deterioration progress indicator indicates the deterioration when the level exceeds a standard level. The VL decreases in accordance with an increase in if and the life indicator indicates its life when the level falls below the standard level. |
