Cfrgtkky

I'm using CircuiTikZ and want to draw a SPST switch that has the same style as the included SPDT switch. Something like the following:

I've experimented with a few things:

documentclass{article}

usepackage{circuitikz}



begin{document}

  begin{enumerate}

    item tikzdraw (0,0) to[nos,o-o] (5,0);

    item tikzdraw (0,0) -- (2.25,0) to[nos,o-o] (2.75,0) -- (5,0);

    item tikzdraw (2.5,0) node[nosshape](sw2){} (0,0) -- (sw2) -- (5,0);

    item tikzdraw (2.5,0) node[nosshape](sw1){} (0,0) to[short,-o] (sw1) to[short,o-] (5,0);

  end{enumerate}

end{document}

The default behavior of nos is seen in item 1; it has no connectors, and adding connectors in the to just puts them at the end of the path, as with all such components.

I was able to produce the look I wanted with the code for item 2, but that requires manually specifying the left and right sides of the switch to be exactly 0.5 units apart (the default width of the nos component). I can use it, but it is not always that straightforward and I would like a simpler method if possible.

I thought I could simplify it by drawing the nos as a node using node[nosshape], which looked like it was going to work when I used the code for item 3. Unfortunately, once I changed to to[short,-o] in order to add the connectors, the lines no longer stopped at the sides of the component, but went to its center point instead, as can be seen in item 4.

How can I simply draw a nos with connectors that doesn't require specifying the sides? And why doesn't the method in item 4 work?

This solution adds ocirc nodes to the switch anchors.

documentclass{standalone}

usepackage{circuitikz}



begin{document}

  begin{circuitikz}

    draw (0,0) to[nos,o-o,n=S1] (5,0)

      node[ocirc] at (S1.e) {}

      node[ocirc] at (S1.w) {};

  end{circuitikz}

end{document}

This may not be a full-fledged answer but more a recipe to construct such elements. What I am proposing to do is to

1. Look in the manual for a similar-looking shape. (I found that the push button has some common elements.


2. Copy the definitions from the relevant files (here they were circuitikz/pgfcircbipoles.tex, pgfcirc.defines.tex and pgfcircpath.tex, which I concluded from grep -r "pushbutton" /usr/local/texlive/2018/texmf-dist/tex/generic/*) to the preamble of your document, enclosed by makeatletter and makeatother.


3. Modify it.

This brought me to

documentclass{article}

usepackage{circuitikz}

makeatletter

ctikzset{bipoles/my switch/height/.initial=.5}

ctikzset{bipoles/my switch/width/.initial=.50}

pgfcircdeclarebipole{}{}{myswitch}{%

ctikzvalof{bipoles/my switch/height}}{ctikzvalof{bipoles/my switch/width}}{

        pgfsetlinewidth{pgfkeysvalueof{/tikz/circuitikz/bipoles/thickness}pgfstartlinewidth}

        pgfpathmoveto{pgfpoint{pgf@circ@res@left}{0pt}}

        pgfpathlineto{pgfpoint{pgf@circ@res@right}{.75pgf@circ@res@up}}

        pgfusepath{draw}

        %

        pgfsetlinewidth{pgfstartlinewidth}        

        pgftransformshift{pgfpoint{pgf@circ@res@left}{0pt}}

        pgfnode{ocirc}{center}{}{}{pgfusepath{draw}}

        pgftransformshift{pgfpoint{2pgf@circ@res@right}{0pt}}

        pgfnode{ocirc}{center}{}{}{pgfusepath{draw}}

}

defpgf@circ@myswitch@path#1{pgf@circ@bipole@path{myswitch}{#1}}

compattikzset{my switch/.style = {circuitikzbasekey, 

/tikz/to path=pgf@circ@myswitch@path}}



makeatother

begin{document}

  begin{enumerate}

    item tikzdraw (0,0) to[my switch] (5,0);

  end{enumerate}

end{document}