\begin{figure}[h!]
        \begin{circuitikz}
            %\draw [help lines] (0,0) grid (15,20);
            \draw (2,2) to [sV,l={12V$_t_t$}] (2,5);
            \draw (2,5) -- (5,5);
            \draw (5,5) -- (5,4);
            \draw (4,3) to [empty diode] (5,4);
            \draw (5,4) to [empty diode] (6,3);
            \draw (4,3) to [empty diode] (5,2);
            \draw (5,2) to [empty diode] (6,3);
            \draw (4,3) -- (4,1);
            \draw (4,1) -- (13,1);
            \draw (13,1) to [R, l={1k\ohm{}}] (13,3); % resistor here!
            \draw (13,3) -- (6,3);
            \draw (5,2) -- (5,0);
            \draw (5,0) -- (2,0);
            \draw (2,0) -- (2,2);
            \draw (9,3) to [capacitor, l={100$_u_f$}] (9,1); %voltage source
        \end{circuitikz}
    \end{figure}