| 摘要 |
PURPOSE:To prevent the change of the screen size due to the brightness of the screen by increasing and decreasing the voltage between the collector and the emitter of the horizontal output transistor by the voltage for adjusting the contrast. CONSTITUTION:The mid-point voltage of a variable resistor 1 rises, the screen goes to be bright, the screen size goes to be larger, and then, the base voltage of the first transistor 11 goes to be higher and the collector voltage falls. For that reason, a constant voltage diode 15 is broke, the second transistor 16 is cut off, the collector voltage rises and the diode 18 is conducted. The emitter voltage of a horizontal output transistor 4 rises, and the voltage between the collector and the emitter goes to be smaller. Thus, the change of the screen size due to the brightness of the screen is suppressed.
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