A 60 W load is connected to the secondary of a transformer whose primary draws line voltage. If a current of 0.54 A flows in the load, what is the current in the primary coil? Comment on the types of transformer being used.

Explanation

Secondary power , `P_(s) = 60 ` W
Secondary current , `I_(S) = 0.54` A
Secondary voltage is
`V_(s) = (P_(s))/(I_(s)) = (60)/(0.54)` = 110 V (approx. )
Primary voltage = 220 V
As `V_(s) lt V_(p)` the transformer is a step-down transformer
` I_(p) V_(p) = V_(S)I_(S)`
`rArr " " I_(p) = (V_(S)I_(S))/(V_(P)) = (110 xx 0.54)/(220)` = 0.27 A