\begin{circuit}1

%Capacitor
\nl \C1 {1F} d
\- 3 d \P1

\atpin C1t
\- 3 u \P2
\- 2 l

%resistor horizontal
\nl \cc \spring1 {$10 \Omega$} l
\- 2 l \P4

% resistor vertical
\- 2 d
\nl \spring2 {$20 \Omega$} d
\vtopin P1

%resistor horizontal
\atpin P4
\- 2 l
\nl \cc \spring3 {$20 \Omega$} l
\- 2 l \P5

% Fuente de tension
\- 2 d
\nl \varU1 {$3u(t)$} d

%Cierre del circuito
\vtopin P1
\htopin P1

% Tension capacitor
\atpin C1t \shift 0.5 0
\put{$+$}
\shift 1 -1 \put {$v_C(t)$}

\atpin C1b \shift 0.5 -0.5
\put{$-$}

% Tension fuente
\atpin varU1t \shift -1.5 0
\put{$+$}

\atpin varU1b \shift -1.5 -0.5
\put{$-$}


\end{circuit}