An Ideal Transformer Example

Consider a simple, transformer with two windings. Find the current provided by the voltage source.

• Winding 1 has a sinusoidal voltage of $120\sqrt{2}\mathrm{\angle }0$° applied to it at a frequency of 60Hz.
• $\frac{N_1}{N_2}=3$
• The combined load on winding 2 is $Z_L=(5+j3)\mathrm{\Omega }$

Solution

$e_1(t)=V_1\cos (\omega t)$

$\omega =2\pi f$, so $\omega =120\pi$

Therefore, $e_1(t)=V_1\cos (120\pi t)$

Now $Z_{th}$ is the impedance seen by the voltage source supplying winding 1.