Draw a labelled diagram of a step-up transformer. State the principle on which it works and obtain the ratio of secondary voltage to primary voltage in terms of number of turns and currents in the two coils.
Show Hint
For an ideal transformer:
\[
\frac{V_s}{V_p}
=
\frac{N_s}{N_p}
\]
\[
\frac{I_s}{I_p}
=
\frac{N_p}{N_s}
\]
A step-up transformer has
\[
N_s>N_p
\]
and therefore
\[
V_s>V_p.
\]