If the primary L1 in Figure above has 40 turns and the secon

If the primary (L1) in Figure above has 40 turns and the secondary (L2) has 10 turns, what is the reflected resistance into the primary if the load resistance is 120 omega? 1920 omega 7.5 omega 480 omega 30 omega

Solution

IN TRANSFORMERS TRANSFORMATION RATIO K=(I1/I2)=(N2/N1)=(V2/V1)

HERE N1=40 TURNS

N2=10 TURNS

TRANSFORMATION RATIO K=(N2/N1)=(10/40)=0.25

THE LOAD RESISTANCE IN SECONDARY=120 OHMS

THIS LOAD RESISTANCE IS SHIFTED TO PRIMARY. IT BECOME (LOAD RESISTANCE)/K^2

120/(K)^2=120/(0.25)^2= 1920 OHMS.