3.如何读懂过压保护电路?(参见图1右下角简化电路见上期)查找保护电路首先要找执行元件,如可控硅,然后找控制极外触发电路。该机过压保护电路由可控硅V819及控制极触发电路V82O稳压二极管(齐纳击穿电压为6.2 V)、限流电阻R822组成。保护电路都有共同的特点:正常工作时它不工作(保护),对整机无影响,只有出现异常(如过压)情况时,才启控保护电路。保护电路都有“检测”电路,设在最能反映特点的部位,如本机设在取样绕组电路之中(如 V820稳压二极管),在开关管从导通转为截止后,取样绕组上的感应电压极性为⑤~+、⑥~-,此时二极管V817截止 3. How to read the overvoltage protection circuit? (See Figure 1 lower right corner of the simplified circuit see the previous period) Find the protection circuit First of all to find the implementation of components, such as thyristor, and then find the control of the very trigger circuit. The machine over-voltage protection circuit by the V819 thyristor and trigger circuit V82O regulator diode (Zener breakdown voltage of 6.2 V), R822 current limiting resistor. Protection circuit has a common characteristic: it does not work (protection) during normal work, no effect on the machine, only when abnormal (such as over-voltage) situation, Kai control circuit protection. Protection circuit has a “test” circuit, located in the most reflect the characteristics of the site, such as the machine is located in the sampling winding circuit (such as V820 Zener diode), the switch from on to off, the sampling winding The induced voltage polarity is ⑤ ~ +, ⑥ ~ -, then the diode V817 ends