交流电直流电转换图解
三步,降压+整流+滤波
1. 首先降压
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172614346-1853519907.jpg)
交流电波形图, 其方向和大小都随时间变化,要得到直流电,要分两个步骤,统一方向,统一大小。
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172614690-2072200264.jpg)
2. 二极管整流
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172615143-2025814265.jpg)
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172615440-1305926925.jpg)
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172615862-234623657.jpg)
但这样电流有太大损耗,可以用4个二极管做成桥式整流电路,
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172616237-1685539810.jpg)
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172616549-302070329.jpg)
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172616878-1253945729.jpg)
得到如下波形图,
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172617331-919073151.jpg)
电流方向得到统一,但电压大小还是波动的,要用电容器再次过滤
3. 电容器滤波稳压
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172617909-809613.jpg)
电容滤波就是利用电容器充放电的原理,外部电压高于极板两端电压时对极板充电,外部电压低于极板两端电压时电容对外放电,从而起到平抑电压的作用。原理图如下,
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172619065-379977710.jpg)
最终电路图如下
![](https://images2015.cnblogs.com/blog/713868/201510/713868-20151010172619659-1640106645.jpg)