How do I achieve consistent font sizing in a tikz circuit?

Question

When creating a circuit using the tikz circuits library, the objects may have a variety of different constructions. There may be labels containing fractions and there may be ordinary paths with labels. I have found that the font sizes are variable, which can make the resulting circuit difficult to read.

Here is my minimal working example:

\documentclass{standalone}

\usepackage{amsmath}

\usepackage{tikz}
\usetikzlibrary{arrows,circuits.ee.IEC,positioning}

\begin{document}

\begin{tikzpicture}[circuit ee IEC,x=2cm,y=1.5cm,
every info/.style={font=\footnotesize},
small circuit symbols,
set inductor graphic=var inductor IEC graphic,
set diode graphic=var diode IEC graphic,
set make contact graphic= var make contact IEC graphic]
% Set the font size

% Let us start with some contacts:
\foreach \contact/\x in {0/0,2/3}
{
\node [contact] (upper contact \contact) at (\x,4) {};
\node [contact] (lower contact \contact) at (\x,0) {};
}
\node [coordinate] (upper right limit) at (6,4) {};
\node [coordinate] (lower right limit) at (6,0) {};

\draw (upper contact 0) to [current direction={near start,info=$I_1$},resistor={info={$\text{R}_1$}},inductor={near end,info={$\text{jX}_1$}}] (upper contact 2);
\draw (upper contact 2) to[current direction={near start,info=$\text{I}_2$},inductor={near end,info={$\text{jX}_2$}}] (upper right limit)
    to[resistor={info={$\frac{\text{R}_2}{\text{s}}$}}] (lower right limit)
    to (lower contact 2)
    to ++(0,1) coordinate (lower fork) {}
    -- ++(-1,0) to[resistor={info={$\text{R}_\text{m}$}}] ++(0,2)
    to ++(1,0) coordinate (upper fork) {}
    to [current direction'={info=$\text{I}_\text{m}$}] (upper contact 2);
\draw (upper fork) -- ++(1,0)
    to[inductor={info={$\text{jX}_\text{m}$}}] ++(0,-2)
    to (lower fork);
\draw[color=blue,thick,->] (upper contact 0) ++(0,-0.5) -- ++(0,-1.5) node[anchor=east] (spannung) {$\text{U}_1$} -- ++(0,-1.5);
\draw[color=blue,thick,->] (upper contact 2) ++(2,-0.5) -- ++(0,-1.5) node[anchor=east] (spannung) {$\text{U}_\text{Err}$} -- ++(0,-1.5);
\draw (lower contact 2) -- (lower contact 0);

\end{tikzpicture}

\end{document}

The U1 and UErr voltage labels are larger than those of the resistances and inductances, and the R_2/s on the right is especially small.

Now, I can put font size parameters in front of the label text, just as I would in a regular LaTeX document, but the problem with this is that the starting size of every text element seems to be different, so I have to adjust the size by trial and error for every label.

If I put something like \large right at the start of the tikzpicture environment, then only the U1 and UErr labels are affected.

Is there a clean way of achieving a consistent font size for every label?

Answer 1

The small resistance and inductance labels are caused by the style every info/.style={font=\footnotesize}, which applies to the part labels. To get the same font size for all text, remove that style, and replace it with every node/.style={font=\large} in your tikzpicture options. To make the fraction use larger text, use \dfrac instead of \frac:

\documentclass[border=5mm]{standalone}

\usepackage{amsmath}

\usepackage{tikz}
\usetikzlibrary{arrows,circuits.ee.IEC,positioning}

\begin{document}

\begin{tikzpicture}[circuit ee IEC,x=2cm,y=1.5cm,
every node/.style={font=\large},
small circuit symbols,
set inductor graphic=var inductor IEC graphic,
set diode graphic=var diode IEC graphic,
set make contact graphic= var make contact IEC graphic]
% Set the font size

% Let us start with some contacts:
\foreach \contact/\x in {0/0,2/3}
{
\node [contact] (upper contact \contact) at (\x,4) {};
\node [contact] (lower contact \contact) at (\x,0) {};
}
\node [coordinate] (upper right limit) at (6,4) {};
\node [coordinate] (lower right limit) at (6,0) {};

\draw (upper contact 0) to [current direction={near start,info=$I_1$},resistor={info={$\text{R}_1$}},inductor={near end,info={$\text{jX}_1$}}] (upper contact 2);
\draw (upper contact 2) to[current direction={near start,info=$\text{I}_2$},inductor={near end,info={$\text{jX}_2$}}] (upper right limit)
    to[resistor={info={$\dfrac{\text{R}_2}{\text{s}}$}}] (lower right limit)
    to (lower contact 2)
    to ++(0,1) coordinate (lower fork) {}
    -- ++(-1,0) to[resistor={info={$\text{R}_\text{m}$}}] ++(0,2)
    to ++(1,0) coordinate (upper fork) {}
    to [current direction'={info=$\text{I}_\text{m}$}] (upper contact 2);
\draw (upper fork) -- ++(1,0)
    to[inductor={info={$\text{jX}_\text{m}$}}] ++(0,-2)
    to (lower fork);
\draw[color=blue,thick,->] (upper contact 0) ++(0,-0.5) -- ++(0,-1.5) node[anchor=east] (spannung) {$\text{U}_1$} -- ++(0,-1.5);
\draw[color=blue,thick,->] (upper contact 2) ++(2,-0.5) -- ++(0,-1.5) node[anchor=east] (spannung) {$\text{U}_\text{Err}$} -- ++(0,-1.5);
\draw (lower contact 2) -- (lower contact 0);

\end{tikzpicture}

\end{document}