\documentclass{standalone}

\usepackage[european,straightvoltages]{circuitikz}

\begin{document}

\begin{circuitikz}
    \draw (0, 0) to [V=$e(t)$] (6, 0)
        to (6, -2)
        to [C, l_=$C$] (4, -2)
        to [cute inductor, l_=$L;r$] (2, -2)
        to [R, l_=$R$] (0, -2)
        to (0, 0);
    \draw[thick, ->] (0.2, -2.3) -- (1.8, -2.3) node [midway, below] {$u_{\mathrm I}$};
    \draw[thick, ->] (0.2, -2.7) -- (5.8, -2.7) node [midway, below] {$u_{\mathrm{II}}$};
    \node [scale=1.7] at (7, -1.1) {$\iff$};
    \draw (8, 0) to [V=$e(t)$] (16, 0)
        to (16, -2)
        to [C, l_=$C$] (14, -2)
        to [R, l_=$r$] (12, -2)
        to [cute inductor, l_=$L$] (10, -2)
        to [R, l_=$R$] (8, -2)
        to (8, 0);
    \draw[thick, ->] (8.2, -2.3) -- (9.8, -2.3) node [midway, below] {$u_{\mathrm I}$};
\end{circuitikz}

\end{document}
