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黑白电视机使用多年后,常出现亮度不足的现象。提高亮度的方法有多种,最常用的方法是在显像管栅阴极上并一只500kΩ～2MΩ的电阻。但此法也有不足之处:(1)当所并电阻阻值过大时效果并不理想;(2)若所并电阻过小,则关机后易出现关机亮点,即在显像管屏幕中心留下荧光粉烧黑痕迹,又会给人在心理造成恐惧感。关机亮点的形成原因是栅极上的负压没有保持足
After years of use of black-and-white TV, often appear insufficient brightness phenomenon. There are many ways to improve the brightness, the most commonly used method is in the CRT gate and a 500kΩ ~ 2MΩ resistance. However, this method also has some shortcomings: (1) when the combined resistance is too large, the effect is not satisfactory; (2) If the combined resistance is too small, the shutdown is prone to shutdown bright spots, that is, leaving fluorescent fluorescence in the center of the tube screen Black traces of burning powder will give people psychological fear. Shutdown bright spot is formed because the negative pressure on the grid does not keep enough