比较以上各式得: R R1 B RaRR/ 2 在已知起动电流比β和电枢电阻R3前提下, 各级起动总电阻为 r=Ra+rst= Br Ra+Rs+rs2=B-r R3=Ra+Rs+Rst2+Rst3=Br Rn=R+Rm+…+队。C 1比较以上各式得： 在已知起动电流比β和电枢电阻Ra前提下， 各级起动总电阻为: = = = =  2 1 1 1 2 2 3 I I R R R R R R a 1 1 3 3 1 2 3 2 2 1 2 1 1 I U R R R R R R R R R R R R R R R R R R R R N a m m a st stm a st st st a a st st a a st a = + + + = =  = + + + = = + + = = + =    