  \centerline{%
    \begin{tikzpicture}[scale=0.7,>=latex]
      \fill[gray!30] (0,0) -- (0,0.3375) -- (4,0.3375) -- (4,0);
      \draw (0,0.3375) -- (4,0.3375);
      %
      \node (IN) at (0.8,1.3) {\small $q_{in}$};
      \draw[thin] (0.6,0.18) -- (IN);
      \fill (0.6,0.15) circle[radius=0.7mm];
      %
      \node (in) at (2.5,1.3) {ström in};
      \draw[thin,<-] (2.33,0.3375) -- (in);
      %
      \fill[gray!60]  (0,0) -- (1.2,0) -- (1.2,-1.5);
      \draw (0,0) -- (1.2,-1.5) -- (1.2,0) -- (4,0);
      %
      \node (UT) at (3.0,-0.8) {\small $q_{ut}$};
      \draw[thin] (0.8,-0.5) -- (UT);
      \fill (0.8,-0.5) circle[radius=0.7mm];
      %
      \node (ut) at (3.0,-1.3) {ström ut};
      \draw[thin,<-] (1.2,-1.05) -- (ut);
     %
      % horizontal axis
      \draw[->] (-0.2,0) -- (0.5+4,0) node[right] {$t$};
      \node at (1.3,0.7) {$T_1$};
      \node at (3.0,0.7) {$T_2$};
      \node at (4.0,0.7) {$T_s$};
      % vertical axis
      \draw[->] (0,-2.8) -- (0,1.5) node[above] {$i_{C_{in}}(t)$};
      \draw (0.0,0.3375) -- (-0.1,0.3375);
      \draw (-0.1,0.5) node[anchor=east] {$I_{in}$};
      \draw (0.0,0) -- (-0.2,0) node[anchor=east] {$-\min i_L$};
      \draw (0,-1.5) -- (-0.1,-1.5) node[anchor=east] {$-\max i_L$};
      \node at (2.0,-3.5) {Del- och gränsdrift};
    \end{tikzpicture}
    %\ind{15mm}
    \hfill
    \begin{tikzpicture}[scale=0.7,>=latex]
      \fill[gray!30] (0,0) -- (0,0.4) -- (4,0.4) -- (4,0);
      \draw (0,0.4) -- (4,0.4);
      \draw[dashed] (4,0.4) -- (8.2,0.4);
      %
      \fill[gray!60]  (0,0) -- (0,-0.5) -- (1.6,-2.5) -- (1.6,0);
      \draw (0,0) -- (0,-0.5) -- (1.6,-2.5) -- (1.6,0) -- (4,0) -- (4,-0.5);
      \draw[dashed] (4,-0.5) -- (5.6, -2.5) -- (5.6,0) -- (8,0) -- (8,-0.5) -- (8.2, -0.75);
      % horizontal axis
      \draw[->] (-0.2,0) -- (0.5+8,0) node[right] {$t$};
      \node at (1.3,0.7) {$T_1$};
      \node at (4.0,0.7) {$T_s$};
      % vertical axis
      \draw[->] (0,-2.8) -- (0,1.5) node[above] {$i_{C_{in}}(t)$};
      \draw (0.0,0.4) -- (-0.1,0.4) node[anchor=east] {$I_{in}$};
      \draw (0.0,-0.5) -- (-0.2,-0.5) node[anchor=east] {$-\min i_L$};
      \draw (0,-2.5) -- (-0.1,-2.5) node[anchor=east] {$-\max i_L$};
      \node at (4.0,-3.5) {Heldrift, fortsättningen antydd};
    \end{tikzpicture}
  }
