TikZ: Controlling new circuit symbols questions

Question

I have created a new circuit symbol for battery source (var battery). There are two problems and one question:

1. I would like for minus to be always horizontal.
2. I would like to control how plus and minus are oriented (e.g. plus up or plus down).
3. Is it possible to change graphical representation of + and - with text symbols?

Regards, Marko

\documentclass[12pt,a4paper]{article}
\input{glava}
\usepackage{tikz}

\begin{document}

\usetikzlibrary{circuits.ee}
\usetikzlibrary{circuits.ee.IEC}

\tikzset{circuit declare symbol = var battery}
\tikzset{set var battery graphic = var battery IEC graphic}
\tikzset{var battery IEC graphic/.style=
  {transform shape, circuit symbol lines, circuit symbol size = width
2.5 height 2.5,
   shape=generic circle IEC, /pgf/generic circle IEC/before
background=
    {\pgfpathcircle{\pgfpoint{0.45pt}{0pt}}{0.1pt}
     \pgfpathcircle{\pgfpoint{-0.45pt}{0pt}}{0.1pt}
     \pgfpathmoveto{\pgfpoint{-1.0pt}{0pt}}
     \pgfpathlineto{\pgfpoint{-0.6pt}{0pt}}
     \pgfpathmoveto{\pgfpoint{1.0pt}{0pt}}
     \pgfpathlineto{\pgfpoint{0.6pt}{0pt}}
     % PLUS SYMBOL
     \pgfpathmoveto{\pgfpoint{-0.45pt}{0.25pt}}
     \pgfpathlineto{\pgfpoint{-0.45pt}{0.65pt}}
     \pgfpathmoveto{\pgfpoint{-0.25pt}{0.45pt}}
     \pgfpathlineto{\pgfpoint{-0.65pt}{0.45pt}}
     % MINUS SYMBOL
     \pgfpathmoveto{\pgfpoint{0.25pt}{0.45pt}}
     \pgfpathlineto{\pgfpoint{0.65pt}{0.45pt}}
     \pgfusepathqstroke}}}

\begin{tikzpicture}[circuit ee IEC,semithick,x=1cm,y=1cm]
\draw (0,0) to [capacitor] (3,0)
to [resistor] (3,2)
to [var battery] (0,2)
to [var battery={info'={$U_3$}}] (0,0);
\end{tikzpicture}

\end{document} 

Answer 1

Here's one solution. It uses \pgftransformresetnontranslation to make sure the minus is typeset the right way round, and then sets a new scaling factor as a multiple of \tikzcircuitssizeunit, which makes sure the symbol scales according to the <size> circuit symbols style.

\documentclass[12pt,a4paper]{article}
%\input{glava}
\usepackage{tikz}

\begin{document}

\usetikzlibrary{circuits.ee}
\usetikzlibrary{circuits.ee.IEC}

\newif\ifreversepolarity
\tikzoption{reversepolarity}[true]{\reversepolaritytrue}


\tikzset{circuit declare symbol = var battery}
\tikzset{set var battery graphic = var battery IEC graphic}
\tikzset{var battery IEC graphic/.style=
  {transform shape, circuit symbol lines, circuit symbol size = width
2.5 height 2.5,
   shape=generic circle IEC, /pgf/generic circle IEC/before
background=
    {
     \pgfpathcircle{\pgfpoint{0.45pt}{0pt}}{0.1pt}
     \pgfpathcircle{\pgfpoint{-0.45pt}{0pt}}{0.1pt}
     \pgfpathmoveto{\pgfpoint{-1.0pt}{0pt}}
     \pgfpathlineto{\pgfpoint{-0.6pt}{0pt}}
     \pgfpathmoveto{\pgfpoint{1.0pt}{0pt}}
     \pgfpathlineto{\pgfpoint{0.6pt}{0pt}}
     \pgfusepathqstroke
     % PLUS AND MINUS SYMBOL
     \pgfgettransform\savedtransform
     \pgftransformshift{\pgfpoint{0.45pt}{0.45pt}}
     \pgftransformresetnontranslations
     \pgftransformscale{0.075\tikzcircuitssizeunit}
     \pgftext{\bf{\ifreversepolarity$-$\else$+$\fi}}
     \pgfsettransform\savedtransform
     \pgftransformshift{\pgfpoint{-0.45pt}{0.45pt}}
     \pgftransformresetnontranslations
     \pgftransformscale{0.075\tikzcircuitssizeunit}
     \pgftext{\bf{\ifreversepolarity$+$\else$-$\fi}}
     \pgfsettransform\savedtransform
     }}}

\begin{tikzpicture}[circuit ee IEC,semithick,x=1cm,y=1cm]
\draw (0,0) to [capacitor] (3,0)
to [resistor] (3,2)
to [var battery,reversepolarity,tiny circuit symbols] (0,2)
to [var battery={info'={$U_3$}},huge circuit symbols] (0,0);
\end{tikzpicture}

\end{document}