DRAWING SCHEMATICS WITH TIKZ AND CIRCUITIKZ

# Drawing Schematics With TikZ And CircuitikZ

## QuickLatex Setup

The code below shows the basic setup to draw a Circuitikz diagram in a Wordpress post using the QuickLatex plugin.

\begin{tikzpicture}
[+preamble]
\usepackage{tikz}
\usepackage[siunitx]{circuitikz}
[/preamble]
% Draw a non-polarized capacitor.
\draw (0,0) to [C, l=$C$] (0,2);
\end{tikzpicture}


Add the actual Circuitikz code between the end of the preamble and the end of the tikzpicture elements.

Sometimes in can be beneficial to add a background to the circuit drawing. This is true when using QuickLatex with Wordpress to render Circuitikz (as this site does), as by default it uses a transparent background, which is good for inline equations, but not so much for circuit drawings.

\useasboundingbox [fill=white!10] (-1,-1) rectangle (3,3);


Tailor the corners of the rectangle to provide the correct size background for your circuit drawing.

## Capacitors

The three types of capacitors used are easily drawn.

% Draw a unpolarised capacitor.
\draw (0,0) to [C, l=$C$] (0,2);
% Draw a polarised capacitor.
\draw (0,0) to [pC, l=$C$] (0,2);
% Draw a variable capacitor.
\draw (0,0) to [vC, l=$C$] (0,2);

 \begin{tikzpicture} [+preamble] \usepackage{tikz} \usepackage[siunitx]{circuitikz} [/preamble] % Draw a non-polarized capacitor. \draw (0,0) to [C, l=$C$] (0,2); \end{tikzpicture} \begin{tikzpicture} [+preamble] \usepackage{tikz} \usepackage[siunitx]{circuitikz} [/preamble] % Draw a polarized capacitor. \draw (0,0) to [pC, l=$C$] (0,2); \end{tikzpicture} \begin{tikzpicture} [+preamble] \usepackage{tikz} \usepackage[siunitx]{circuitikz} [/preamble] % Draw a variable capacitor. \draw (0,0) to [vC, l=$C$] (0,2); \end{tikzpicture} Unpolarised capacitor. Polarised capacitor. Variable capacitor.

## Op-Amps And Comparators

Op-amps and caparators share the same symbol.

\draw
% Draw an op-amp
(0,0) node[op amp] (opamp) {}
(opamp.+) node[left] {$v_+$}
(opamp.−) node[left] {$v_−$}
(opamp.out) node[right] {$v_o$}
;

\begin{tikzpicture}[scale=1]
[+preamble]
\usepackage{tikz}
\usepackage[siunitx]{circuitikz}
[/preamble]
\draw
% Draw an op-amp
(0,0) node[op amp] (opamp) {}
(opamp.+) node[left] {$v_+$}
(opamp.−) node[left] {$v_−$}
(opamp.out) node[right] {$v_o$};
\end{tikzpicture}


## Dashed Lines

It took me awhile to get dashed lines to work, here is the correct way to draw them:

% Make sure to use a separate draw command for dashed lines,
% rather than tacking it onto another one!
\draw[dashed]
(-0.5,0) -- (2,0);


Make sure to use a separate draw command for dashed lines, rather than tacking it onto another one, otherwise you will find all lines in that draw command will become dashed.