直流电压的测量方法步骤如下:
1、准备一个数字万用表,将档位打到直流电压测量档,量程选择了最大20V,演示测量3.3V的直流电压。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/3b292df5e0fe99251bb8bcc926a85edf8cb171f7?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
2、将目标测量直流电压的电路板插上供电线上电,或者直接测量干电池的两端。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/32fa828ba61ea8d33d96a19d850a304e241f58f7?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
3、将红黑表笔分别对应要测量的电源的正极和负极,红色对应正极,黑色对应负极。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/8694a4c27d1ed21bef7dfb7cbf6eddc450da3ff7?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
4、红黑表笔接触好电源的正负极之后,即可从数字万用表的显示里面看到直流电压的读数。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/4afbfbedab64034f7b7a179fbdc379310b551df7?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
5、若显示为“1”,则表明量程太小,那么就要加大量程后再测量。若在数值左边出现“-”,则表明表笔极性与实际电源极性相反,此时红表笔接的是负极。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/3812b31bb051f8199f92d6d3c8b44aed2f73e7f0?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)