“R总=R1R2.Rn/R1+R2+.+Rn”肯定不对
1/R总=1/R1+1/R2+.+1/Rn①
={[R2R3…Rn]/[R1R2…Rn]}+{[R1R3…Rn]/[R1R2…Rn]}+.+{[R1R2…R(n-1)]/[R1R2…Rn]}②
={[R2R3…Rn]+[R1R3…Rn]+…+[R1R2…R(n-1)]}/{R1R2…Rn}③
①通过同分变成②,然后加在一起变成③
最后移项得,
R总={R1R2…Rn}/{[R2R3…Rn]+[R1R3…Rn]+…+[R1R2…R(n-1)]}
其实我觉得多个电阻(两个以上)还是用1/R总=1/R1+1/R2+.+1/Rn带进去算好些