| 摘要 |
PURPOSE:To carry out gamma correction without adversely affecting the color repeatability by making three diodes and their cathodes common so as to connect them to bases and providing one transistor for executing a switching action with respect to the reference voltage of an emitter and a gamma correction amount adjusting resistance connected serially to the emitter. CONSTITUTION:If a voltage at an intersection between a resistance 17 and a variable resistance 19 is set so that a transistor 24 can start turning on with a certain conductive resistance the moment the base voltage of a transistor 4 reaches the voltage subjected to the gamma correction, the base voltage of a transistor 20 rises, and emitter voltages of transistors 5, 6 and 7 also rise. Accordingly the rising ratios of the voltages across bases and emitters of the transistors 5, 6 and 7 can be simultaneously dropped. Thus the gamma correction is uniformly applied to signals R, G and B and a color run can be prevented.
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