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本文介绍的电源纹波业余测量法同样适用于彩色电视机中各电源退耦电路的检查。这对排除因电源退耦不良引起的各种特殊故障,往往起着事半功倍的作用。一台46cm(17英寸)熊猫牌黑白电视机,在收看过程中屏幕上部不时地出现鱼鳞状干扰现象。经一位初学者检修,未能查出故障原因,后转送我处。笔者认为:当电视画面上出现干扰现象(机外干扰除外)时,首先应检查各电源退耦电路是否正常,测量一下各直流供电电压中的纹波电压是否超标。纹波电压是指整机正常工作时电源输出中含有的交流脉动分量。理论上,对于12V稳压电源的纹波电压的有效值一般应在10mV以下,若以峰值电压计
This article describes the power supply ripple amateur measurement method is also applicable to the color TV in the power decoupling circuit check. This is to exclude a variety of special failures caused by poor power decoupling, often play a multiplier effect. A 46cm (17 inch) panda black and white TV set, during the viewing process from time to time on top of the fish scaly interference phenomenon. After a beginner overhaul, failed to find the cause of the malfunction, after forwarding to my office. The author believes that when the TV screen appears interference (except interference outside the machine), first of all should check the power decoupling circuit is normal, measure the DC power supply voltage ripple voltage is excessive. Ripple voltage refers to the normal operation of the machine when the power output contains the exchange of pulsatile components. In theory, the effective value of ripple voltage of 12V regulated power supply should generally be below 10mV. If peak voltage meter