\begin{texdraw}
\drawdim cm

% abcisas
\move(-0.5 0)
\avec(2 0)
\rmove(0 -0.2)
\textref h:C v:T \htext{$t$}

% ordenadas
\move(0 -0.5)
\avec(0 2.6)
\rmove(-0.2 0)
\textref h:R v:C \htext{$v(t)$}

% La linea gruesa
\linewd 0.075
\move(-0.5 0)
\lvec(0 0)
\lvec(0 1)
\lvec(2 1)


\move(-0.2 1)
\textref h:R v:C \htext{$\frac{1}{C}$}

\end{texdraw}