Set label name on two lines in CircuiTikZ

Question

I'm a very beginner in using circuitikz in my tex documents.

I'd like to obtain a label that shows both the part name and the component value. Looking in this forum I found this solution:

\documentclass{article}
\usepackage[siunitx]{circuitikz}
\begin{document}
\begin{circuitikz}
\draw (0,0) to  [R, l_={\parbox{1cm}{\centering R$_1$\\\SI{510}{\ohm}}}] (2,0);
\end{circuitikz}
\end{document}

The output is good but I'm not very satisfied by the code.

Is there any simpler/easier solution?

Answer 1

Here I provide a different solution from the one suggested by Peter.

Basically, I define a new kind of label lx that accepts two commands: the first one is the component name (for example R_1, C_1) and the second is dedicated to the component value. Its behaviour is similar to the standard l, therefore the followings:

• lx_=...
• lx^=...

hold. In conclusion, the command should be used as:

lx_={component_name and component_value}

For instance:

lx^={C$_1$ and \SI{1}{\farad}}

---

Here is the complete example:

\documentclass{article}
\usepackage[siunitx]{circuitikz}

\makeatletter
\ctikzset{lx/.code args={#1 and #2}{ 
  \pgfkeys{/tikz/circuitikz/bipole/label/name=\parbox{1cm}{\centering #1  \\ #2}}
    \ctikzsetvalof{bipole/label/unit}{}
    \ifpgf@circ@siunitx 
        \pgf@circ@handleSI{#2}
        \ifpgf@circ@siunitx@res 
            \edef\pgf@temp{\pgf@circ@handleSI@val}
            \pgfkeyslet{/tikz/circuitikz/bipole/label/name}{\pgf@temp}
            \edef\pgf@temp{\pgf@circ@handleSI@unit}
            \pgfkeyslet{/tikz/circuitikz/bipole/label/unit}{\pgf@temp}
        \else
        \fi
    \else
    \fi
}}

\ctikzset{lx^/.style args={#1 and #2}{ 
    lx=#2 and #1,
    \circuitikzbasekey/bipole/label/position=90 } 
}

\ctikzset{lx_/.style args={#1 and #2}{ 
    lx=#1 and #2,
    \circuitikzbasekey/bipole/label/position=-90 } 
}
\makeatother

\begin{document}
\begin{circuitikz}
\draw (0,-3) to  [R, lx_={R$_1$ and \SI{510}{\ohm}}] (2,-3);
\draw (6,-3) to  [C, lx^={C$_1$ and \SI{1}{\farad}}] (8,-3);
\end{circuitikz}
\end{document}

Result:

Answer 2

I know that this answer will give me one of that creepy badges... ;-) but we are in Halloween, so why not?

I did a more flexible version of Claudio's ctikz-lx (to fix some alignment problem in case of long labels) and I think it's my duty to share it. I called it ctikz-ly.

The packages is here (manual in comments):

\NeedsTeXFormat{LaTeX2e}[1996/06/01]
\ProvidesPackage{ctikz-ly}[2018/10/25 stacked labels for circuitikz]
%
% stacked labels by Romano Giannetti romano@rgtti.com
% heavily based on Claudo Fiandrinos's https://tex.stackexchange.com/a/65792/38080
% \expandafter trick inspired by Matthew Leingang's https://tex.stackexchange.com/a/12272/38080
%
% labels are in a tabular, globally aligned:
%        vertically with key ly valign (default c)
%        c: center t: top b: bottom
%        horizontally with key lx align (default l)
%        l: left c: centered r: right
% you can switch sides using ly_=... and ly^=...
% syntax is ly_ = line1 and line2 (same for ly^)
%
\ctikzset{%
    ly valign/.store in=\ly@valign, ly valign=c,
    ly halign/.store in=\ly@halign, ly halign=l,
}
\ctikzset{ly/.code n args={2}{
  \pgfkeys{/tikz/circuitikz/bipole/label/name=%
        \bgroup
        \setlength{\tabcolsep}{2pt}%
        \def\ly@tabu{\tabular[\ly@valign]}%
        \expandafter\ly@tabu\expandafter{\ly@halign}%
        #1\\ #2%
        \endtabular
        \egroup
    }%
    \ctikzsetvalof{bipole/label/unit}{}
    \ifpgf@circ@siunitx
        \pgf@circ@handleSI{#2}
        \ifpgf@circ@siunitx@res
            \edef\pgf@temp{\pgf@circ@handleSI@val}
            \pgfkeyslet{/tikz/circuitikz/bipole/label/name}{\pgf@temp}
            \edef\pgf@temp{\pgf@circ@handleSI@unit}
            \pgfkeyslet{/tikz/circuitikz/bipole/label/unit}{\pgf@temp}
        \else
        \fi
    \else
    \fi
}}
\ctikzset{ly^/.style args={#1 and #2}{
        ly={#1}{#2},
    \circuitikzbasekey/bipole/label/position=90 }
}
\ctikzset{ly_/.style args={#1 and #2}{
        ly={#1}{#2},
    \circuitikzbasekey/bipole/label/position=-90 }
}
\endinput

and a MWE using it, showing several combinations:

\documentclass[border=10pt]{standalone}
\usepackage[siunitx, oldvoltagedirection]{circuitikzgit}
\usepackage{ctikz-ly}
\ctikzset{tripoles/mos style/arrows, bipoles/thickness=1, }
\makeatletter
\makeatother
\begin{document}
\begin{circuitikz}[ american, ]
    %
    % default is ly halign=l, ly valign=c 
    %
    \begin{scope}[color=blue]
        \draw (0,0) to[R, ly_=$R_{CC}$ and \SI{4.7}{k\ohm},            , ly valign=t] (3,0);
        \draw (0,0) to[R, ly_=$R_{CC}$ and \SI{4.7}{k\ohm},            ,            ] (0,3);
        \draw (0,0) to[R, ly_=$R_{CC}$ and \SI{4.7}{k\ohm}, ly halign=c, ly valign=b] (-3,0);
        \draw (0,0) to[R, ly_=$R_{CC}$ and \SI{4.7}{k\ohm}, ly halign=r, ly valign=c] (0, -3);
    \end{scope}
    \begin{scope}[xshift=6cm, color=red]
        \draw (0,0) to[R, ly^=$R_{CC}$ and \SI{4.7}{k\ohm}, ly halign=c, ly valign=b] (3,0);
        \draw (0,0) to[R, ly^=$R_{CC}$ and \SI{4.7}{k\ohm}, ly halign=c,            ] (0,3);
        \draw (0,0) to[R, ly^=$R_{CC}$ and \SI{4.7}{k\ohm},            , ly valign=t] (-3,0);
        \draw (0,0) to[R, ly^=$R_{CC}$ and \SI{4.7}{k\ohm}, ly halign=c, ly valign=t](0, -3);
    \end{scope}
\end{circuitikz}
\end{document}

which results in: