\documentclass{standalone}

\usepackage[european,straightvoltages]{circuitikz}

\begin{document}

\begin{circuitikz}
	\draw (6, 0) to [V=$e(t)$] (0, 0)
		to [short, i=$i(t)$] (0, 3)
		to (1, 3)
		to (1, 2)
		to [cute inductor, l=$L$] (3, 2)
		to [R=$R$] (5, 2)
		to (5, 4)
		to [C, l_=$C$] (3, 4)
		to [R, l_=$R$] (1, 4)
		to (1, 3)
		(5, 3) to (6, 3)
		to (6, 0);
	\node [scale=1.7] at (7, 1.45) {$\iff$};
	\begin{scope}[shift={(8, 0)}]
		\draw (4, 0) to [V=$e(t)$] (0, 0)
			to [short, i_=$i(t)$] (0, 3)
			to [R=$\underline Z_{eq}$] (4, 3)
			to (4, 0);
	\end{scope}
\end{circuitikz}

\end{document}
