更新时间2019-05-22 11:22:16
us1=20v us2=15v R1=5Ω R2=3Ω R3=2Ω 用叠加原理求I3
us2短路,us1单独作用:
总电流 i = us1/( R1 + R2//R3 ) = 20/( 5 + 6/5 ) = 100/31;
i31 = i * R2/( R2 + R3 ) = (100/31) * 3/( 3 + 2 ) = 60/31;
us1短路,us2单独作用:
总电流 i = us2/( R2 + R1//R3 ) = 15/( 3 + 10/7 ) = 105/31;
i32 = i * R1/( R1 + R3 ) = (105/31) * 5/( 5 + 2 ) = 75/31;
I3 = i31 + i32 = 60/31 + 75/31 = 135/31 A 。
保持电路不变,去掉其中一个电源,算i3,再更换为另1个电源求i3,将2次i3相加,如果方向不同为负