Question

A $220$ volt input is supplied to a transformer.The output circuit draws a current of $2.0ampere$ at $440$ volts. If the efficiency of the transformer is $80\%$, the current drawn by the primary winding`` of the transformer is

• A. $3.6ampere$
• B. $2\cdot 8ampere$
• C. $2\cdot 5ampere$
• D. $5\cdot 0ampere$

Answer 1

The correct option is D $5\cdot 0ampere$

A 220 volt input is supplied to a transformer.The output circuit draws a current of 2.0 ampere at 440 volts. If the efficiency of the transformer is 80%, the current drawn by the primary windings of the transformer is

$\eta =efficiency=\frac{Outputpower}{InputPower}=\frac{V_s{I}_s}{V_p{I}_p}$.

$I_p=\frac{440\times 2}{\frac{80}{100}\times 220}=5A$