% Author: Prof. Dr. Matthias Jung, DL9MJ
% Year: 2024
\begin{tikzpicture}
    \pgfplotsset{every tick label/.append style={rotate=-90}}
    \begin{axis}[%
        axis lines=middle,
        %yticklabel=\empty,
        xmin=0,
        xmax=500,
        ymin=0,
        ymax=6,
        xtick={0,50,100,200,300,400},
        xticklabels={
            \qty{0}{\ohm},
            \qty{50}{\ohm},
            \qty{100}{\ohm},
            \qty{200}{\ohm},
            \qty{300}{\ohm},
            \qty{400}{\ohm}
        },
        ytick={0,5},
        yticklabels={
            0,
            $P_\text{max}$
        },
        yticklabel style={rotate=90},
        axis line style={-Triangle},
        xticklabel style={/pgf/number format/.cd,fixed,precision=1,use comma,fixed,fixed zerofill},
        xlabel style={at={(ticklabel* cs:1)},anchor=north},
        ylabel style={at={(ticklabel* cs:1)},anchor=north east},
        ylabel={$P_\text{L}$},
        xlabel={$R_\text{L}$},
        scale only axis,
        height=5cm,
        width=\linewidth*\getDarcImageFactor        
    ]
    \addplot[
        DARCred,
        no marks,
        domain=0:500,
        samples=1000,
        ultra thick
    ] {1000*x/((50+x)*(50+x))};

    \draw[DARCgray,thin, dashed](axis cs:50,5) -- (axis cs:50,0);
    \draw[DARCgray,thin, dashed](axis cs:0,5)  -- (axis cs:50,5);
    \draw[DARCred](axis cs:50,5) node[anchor=south west](){Leistungsoptimum};
 
    \end{axis}
\end{tikzpicture}%