Jawabanmu

2014-06-12T11:16:48+07:00
Np / Vp = Ns / Vs

1200 / 180 = 80 / Vs

20 / 3 = 80 / Vs

20 . Vs = 3 . 80

Vs = 12

Vs = Is . R  -- > 12 = Is . 4 -- > Is = 3

Vp = Ip . R -- > 180 = Ip . 4 -- > Ip = 45