答:5只串联(15×5=75)得75Ω.
3只并联(15÷3=5)得5Ω,2只串联(15×2=30)得30Ω,5Ω与30Ω串联得35Ω.
2只并联得7.5Ω,2只并联得7.5Ω,1只15Ω,3项串联得30Ω.
2只并联得7.5Ω,3只并联得5Ω,2项串联得12.5 Ω.
5只并联得3Ω.
答:5只串联(15×5=75)得75Ω.
3只并联(15÷3=5)得5Ω,2只串联(15×2=30)得30Ω,5Ω与30Ω串联得35Ω.
2只并联得7.5Ω,2只并联得7.5Ω,1只15Ω,3项串联得30Ω.
2只并联得7.5Ω,3只并联得5Ω,2项串联得12.5 Ω.
5只并联得3Ω.