# LC circuit with circuitikz

I have to draw a LC circuit, with inductor of inductance L and capacitor of capacitance C. I'de like to add the current flow (say clockwise) and a + near one of the surfaces and a - near the other one.

This is what I've come up with, but it lacks of some details I'd like to have instead.

\begin{circuitikz} \draw
(0,0) -- (3,0)
(0,3) -- (3,3)
(0,0) to[L] (0,3)
(3,0) to[C] (3,3)
;
\end{circuitikz}


Can you draw it for me using circuitikz, please?

• Can you demonstrate what you want to draw visually? There might be others like me that are familiar with latex but not LC circuit concepts. Commented Jun 5, 2020 at 20:07
• I've added a picture, hope it is clearer now :) Commented Jun 5, 2020 at 20:36
• Commented Jun 6, 2020 at 2:08
• @LorenzoBenedetti did the answer below meet your requirement Commented Jun 13, 2020 at 15:57
• @jsbibra yep, it did Commented Jun 14, 2020 at 16:08

Like this?

\documentclass[margin=3mm]{standalone}
\usepackage[oldvoltagedirection]{circuitikz}

\begin{document}
\begin{circuitikz}
\draw
(0,0) -- (3,0)
(0,3) -- (3,3)
(0,0) to[L, l^=$L$] (0,3)
(3,0) to[C, l^=$C$,name=c] (3,3)
;
\node at (c.300)[above]{$+$};
\node at (c.60)[above]{$+$};
\node at (c.120)[below]{$-$};
\node at (c.240)[below]{$-$};
\draw [-latex](1,-0.25)--(2,-0.25)node[midway,below]{$i$};
\draw [latex-](1,3.25)--(2,3.25)node[midway,above]{$i$};
\end{circuitikz}
\end{document}


• I stil need the electrical current, how to add it? thank you Commented Jun 5, 2020 at 22:26
– user31034
Commented Jun 5, 2020 at 23:08

@Lorenzo wanted a clockwise current so-- three options -- --with an arrow on the circuit -- with dashed arrow loop inside the circuit --with continuous arrow loop inside the circuit

Fill up the basic package

\documentclass[margin=2mm,tikz]{standalone}
\usepackage[american]{circuitikz}
\usetikzlibrary{backgrounds,calc,positioning}
\begin{document}

\begin{tikzpicture}[x=3cm,y=3cm]

\end{tikzpicture}
\end{document}
% I use a tikzpicture instead of a circuitikz here because
% the standalone package does weird things with the paper
% size when using a circuitikz environment. Feel free to
% change this in your document.
% We choose a base length of 3cm to simplify our coordinate
% calculations. Adjust as needed. Default is 1cm by the way.


Next step --
Define all coordinates. Not strictly necessary, but it makes for cleaner code, in my humble opinion.

\coordinate[label=A1]       (A1)  at (1,0);
\coordinate[label=B1]       (B1)  at (2,0);
\coordinate[label=C1]       (D1)  at (1,-1);
\coordinate[label=D1]       (C1) at (2,-1);


Next -- Draw part of the circuit. You might need more than one draw command, depending on how you do things.

\draw   (A1)
to      (B1)
to [C, name=c, l_=$C_{1}$]        (C1)
to      (D1)
to [L,l_=$L_1$,color=magenta]     (A1);


\node at (c.north west)[yshift=4pt,  xshift=-6pt] {$+$};
\node at (c.north east)[yshift=-4pt, xshift=-6pt] {$-$};


Next -- Helper lines-- Remove the 'dashed' parameter for a normal line. This part uses the 'calc' library from TikZ for coordinate calculations.

NOTE: The corner radius has to be adjusted manually if you adjust the base x and y lengths in the optional argument for the tikzpicture/circuitikz environment.

\draw[red,rounded corners=0.2cm,-latex]
($(A1) + (0.175,-0.5)$)
-- ($(A1) + (0.175,-0.1)$)
-- ($(B1) - (0.175, 0.1)$)
-- ($(C1) + (-0.175, 0.1)$)
-- ($(D1) + (0.175, 0.1)$)
;


\node at ($(D1) + (0.4, 0.15)$) {$i$};


Complete--

\documentclass[margin=2mm,tikz]{standalone}
\usepackage[american]{circuitikz}
\usetikzlibrary{backgrounds,calc,positioning}
\begin{document}

\begin{tikzpicture}[x=3cm,y=3cm]
\coordinate[label=A1]       (A1)  at (1,0);
\coordinate[label=B1]       (B1)  at (2,0);
\coordinate[label=C1]       (D1)  at (1,-1);
\coordinate[label=D1]       (C1) at (2,-1);

\draw
(A1)
to (B1)
to [C, name=c, l_=$C_{1}$]        (C1)
to (D1)
to [L,l_=$L_1$,color=magenta]     (A1);

\node at (c.north west)[yshift=4pt, xshift=-6pt] {$+$};
\node at (c.north east)[yshift=-4pt, xshift=-6pt] {$-$};

\draw[red,rounded corners=0.2cm,-latex]
($(A1) + ( 0.175,-0.5 )$)
-- ($(A1) + ( 0.175,-0.1)$)
-- ($(B1) - ( 0.175, 0.1)$)
-- ($(C1) + (-0.175, 0.1)$)
-- ($(D1) + (0.175, 0.1)$)
;
\node at ($(D1) + (0.4, 0.15)$) {$i$};
\end{tikzpicture}
\end{document}


For dashed lines -- replace with

\draw[red,dashed, thick,rounded corners=0.2cm,-latex]
($(A1) + ( 0.175,-0.5 )$)
-- ($(A1) + ( 0.175,-0.1)$)
-- ($(B1) - ( 0.175, 0.1)$)
-- ($(C1) + (-0.175, 0.1)$)
-- ($(D1) + (0.175, 0.1)$)
;


For continuous lines instead of dashed lines replace with --

\draw[red,rounded corners=0.2cm,-latex]
($(A1) + ( 0.175,-0.5 )$)
-- ($(A1) + ( 0.175,-0.1)$)
-- ($(B1) - ( 0.175, 0.1)$)
-- ($(C1) + (-0.175, 0.1)$)
-- ($(D1) + (0.175, 0.1)$)
;