| 摘要 |
PURPOSE:To keep discharge current flowing in a laser tube constant, by keeping a reference voltage constant even if an input voltage is fluctuated by the combination of comparing amplifiers and a Zener diode. CONSTITUTION:The voltage of a Zener diode for a reference power source is kept constant by a comparing amplifier. The output voltage VS of the Zener diode is made constant. A circuit, which keeps the discharge current in a laser tube 5 constant even if voltages at power source input terminals 13 and 14 are fluctuated, is provided. A current Iz flowing through the Zener diode 12 is controlled at a constant level by the comparing amplifier 15. The output voltage VS of the Zener diode 12 is also kept at a constant level. A comparing amplifier 10 compares and amplifiers said Vs and a detected voltage VO and controls a switching circuit 1. Therefore, the discharge current between an anode 6 and a cathode 7 in the laser tube 5 is kept constant. |
