Question

In a step - down transformer having primary to secondary turn ratio `20:1` the input voltage applied is `250V` and output current is `8A` Assuming `100%` efficiency calculate the
(a) voltage across secondary coil
(b) current in primary coil
(c) power output .

Answer 1

`N_(s)/(N_(P)) = (1)/(20) V_(p) = 250 V, i_(s) = 8A`
`(V_(s))/(V_(p)) = N_(s)/(N_(p)) implies V_(s) = (N_(s))/(N_(p)) xx V_(p) = (1)/(20) xx 250 = 12.5V`
`(i_(p))/(i_(s)) = N_(s)/N_(p) implies i_(p) = (N_(s))/(N_(p) )i_(s) = (1)/(20) xx 8= 0.4A`
Power output `= V_(s) i_(s) i_(s) = 12.5 xx 8 =100 W` .