为方便验证结果设12Ω电阻电流为Ix，方向与Ir相同。\r 开关闭合瞬间电容等效为通路，用电流叠加法分析，先去掉电容\r 电流源电阻 1/R = 1/12+1/6+1/4 ，R = 2Ω\r 电流源电动势为 12V，电流Ic1 =-12V/4Ω = -3A ,Ir1 = 12V/6Ω = 2A ,Ix1=12V/12Ω = 1A\r 电容两端电阻 R = 12*6/（12+6）+4 = 8Ω\r 电流Ic2 = 6V/8Ω = 3/4A ,Ir2 = 3V/6Ω = 1/2A, Ix2 = 3V/12Ω =1/4A\r Ic = Ic1+Ic2 = -9/4A\r Ir = Ir1 + Ir2 = 5/2A\r Ix = Ix1 + Ix2 = 5/4A\r 验证： I总 = -Ic + Ir+ Ix = 6A \r