| 摘要 |
A laser diode supply circuit comprises a laser diode (LD1) connected in series with a junction transistor (TR1). The base of the transistor is controlled through a second transistor (TR2) receiving at its base a control voltage developed by the series connection of a photo-diode (LD2) and a variable resistor (VR1). The photo-diode is optically coupled with the laser diode, such that as the power output of the laser diode increases beyond a desired value the control voltage exceeds the threshold value of the second transistor (TR2). |
