AUTOMATIC WHITE COLOR CONTROL CIRCUIT FOR COLOR TELEVISION PICTURE RECEIVER

摘要

PURPOSE:To provide the adequate white color to the TV viewer with no effect of the ambient light, by varying the amplification factor of the video transistor in accordance with the luminance level of the ambient light. CONSTITUTION:The resistance value of the ambient light detecting element 51 varies according to the luminance level of the ambinet light. This variation of the resistance value is converted into the variation of the output voltage of the transistor 53 and then the variation of the base bias of the transistor 61. According to the variation of the base bias of the transistor 61, the amplification factor of the video transistor 6 in the blue axis group changes to secure a compensation for the white balance.