| 摘要 |
PURPOSE: A device for automatically adjusting the luminance of a monitor is provided to maintain raster luminance of the monitor at a constant level by uniformly maintaining a deviation between a G1 voltage and the cutoff voltage. CONSTITUTION: A high voltage detecting circuit(200) receives a high voltage from an FBT(Fly Back Transformer) to output a constant voltage. A reference voltage controlling circuit(210) adjusts and outputs a cutoff voltage according to the voltage output from the high voltage detecting circuit. A cutoff voltage controlling circuit(220) receives the cutoff voltage from the reference voltage controlling circuit, and outputs the inputted cutoff voltage to an R/G/B(Red/Green/Blue) cathode. The high voltage detecting circuit including resistances(R1,R2) and a zener diode(ZD1) divides voltage(Va) output from the FBT by the resistances, and outputs the constant voltage by adding a voltage fed to the resistance(R2) and a voltage fed to the zener diode.
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