Question

15. A step down transformer connected to main supply of 240V is made to operate a 12 V.36 W lamp Ignoring power losses in the transformer estimate (1) current in the primarycircuit(ii) The transformer turns ratio​

Answer 1

Answer:

Ns / Np  = 1 / 20    &    Ip = 0.15 A

Explanation:

Vp =240 v                &        Vs = 12 v              &   Po = 36 W

Vs Is = 36 W           ,         Vs / Vp = Ip / Is

Is = 36 /12                ,        Vs / Vp x Is = Ip

Is = 3 A                     ,        Ip = 3 x 12/240

Vs / Vp =  Ns / Np      ,       Ip = 0.15 A

Ns / Np  = 12 / 240

Ns / Np  = 1 / 20