| 摘要 |
PURPOSE:To obtain an ABL circuit of good quality and of safety with limiting voltage n the abnormal time of the ABL circuit by connecting a Zener diode between an ABL winding terminal in a fly-back transformer and the earth. CONSTITUTION:The one end of a high-voltage winding part in a flyback transformer 1 is connected to the anode of a CRT and the other end of it to a luminance control circuit through resistors 4 and a7. A Zener diode 2 and a capacitor 3 are connected between the other end and the earth and a diode 5 is connected between the connecting point of resistors 4 and 7 and the earth. Also, a power source +B is connected to the diode 5 through a resistor 6. And the beam current of the CRT is controlled according to the current of the transformer. And also, even when overcurrent is flowed under the abnormal condition, abnormal voltage is not impressed on the capacitor 3 by the Zener diode 2 and the ABL circuit of good quality and of safety is obtained.
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