Question 434: AC fundamentals

Question

A 220 V input is supplied to a transformer. The output circuit draws a current of 2.0 A at 440 V . If the ratio of output to input power is 0.8 , then the current drawn by primary winding is

Accepted Answer

Given, input voltage supplied to transformer,
$$V_1=220 \mathrm{~V}$$
Current at output circuit of transformer,
$$\begin{gathered}
i_2=2 \mathrm{~A} \
V_2=440 \mathrm{~V} \
\frac{	ext { Output power }\left(P_2ight)}{	ext { Input power }\left(P_1ight)}=0.8 \Rightarrow \frac{V_2 i_2}{V_1 i_1}=0.8 \
\frac{440 	imes 2}{220 	imes i_1}=0.8 \
\frac{4}{i_1}=0.8 \Rightarrow i_1=\frac{4}{0.8}=5 \mathrm{~A}
\end{gathered}$$
Hence, current drawn by the primary windings is 5 A .

Answer

3.6 A

Answer

5.0 A

Answer

2.5 A

Answer

2.8 A

AC fundamentals

A 220 V input is supplied to a transformer. The output circuit draws a current of 2.0 A at 440 V . If the ratio of output to input power is 0.8 , then the current drawn by primary winding is

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