Position labels inside circuitikz reisistors

Question

I'm trying to position the labels for (european) resistors in circuitikz inside the resistors, but it automatically positions them besides the boxes and I get this:

\documentclass[12pt,a4paper]{article}
\usepackage{circuitikz}
\begin{document}

\begin{circuitikz}[scale = 0.5,european]
            % start points
            \coordinate[label=above:B] (B) at (0,0);
            \coordinate[label=above:A] (A) at (0,5);
            \foreach \i in {A,B} {
                \fill (\i) circle (2pt);
            }
            \draw (B) to (4,0) to (4,-1) to[R, label={$2R$}] (8,-1) to (8,0);
            \draw (4,0) to (4,1) to[R, label={$2R$}] (8,1) to (8,0) to (12,0) to[R, l_={$R$}] (12,5) to[] (11,5);
            \draw (A) to[] (1,5) to (1,3) to[R, label={$2R$}] (11,3) to[] (11,5);
            \draw (1,5) to[R, label={$R$}] (6,5) to[R, label={$R$}] (11,5);
        \end{circuitikz}

\end{document}

Answer 1

Well, this is not really supported. It would be wrong with most of the components, and the idea of circuitikz is that you can switch from european to american and still have a valid circuit...

But you can trick it into working:

\documentclass[12pt,a4paper]{article}
\usepackage[RPvoltages]{circuitikz}
\begin{document}

\begin{circuitikz}[scale = 0.5,european]
            % start points
            \coordinate[label=above:B] (B) at (0,0);
            \coordinate[label=above:A] (A) at (0,5);
            \foreach \i in {A,B} {
                \fill (\i) circle (2pt);
            }
            % name the node, and...
            \draw (B) to (4,0) to (4,-1) to[R, name=R1] (8,-1) to (8,0);
            % add the thing
            \node  at (R1.center) {$R$};
            \draw (4,0) to (4,1) to[R, label={$2R$}] (8,1) to (8,0) to (12,0) to[R, l_={$R$}] (12,5) to[] (11,5);
            \draw (A) to[] (1,5) to (1,3) to[R, label={$2R$}] (11,3) to[] (11,5);
            \draw (1,5) to[R, label={$R$}] (6,5) to[R, label={$R$}] (11,5);
        \end{circuitikz}
\end{document}

You can also automate them, using a consistent naming scheme:

\documentclass[12pt,a4paper]{article}
\usepackage[RPvoltages]{circuitikz}
\begin{document}
\begin{circuitikz}[scale = 0.5,european]
            % start points
            \coordinate[label=above:B] (B) at (0,0);
            \coordinate[label=above:A] (A) at (0,5);
            \foreach \i in {A,B} {
                \fill (\i) circle (2pt);
            }
            % name the nodes Rx for R and 2Rx for 2R, and...
            \draw (B) to (4,0) to (4,-1) to[R, name=R1] (8,-1) to (8,0);
            \draw (4,0) to (4,1) to[R, name=2R1] (8,1) to (8,0) to (12,0) to[R, name=R2] (12,5) to[] (11,5);
            \draw (A) to[] (1,5) to (1,3) to[R, name=2R2] (11,3) to[] (11,5);
            \draw (1,5) to[R, name=R3] (6,5) to[R, name=R4] (11,5);
            % add labels
            \foreach \n in {1,...,4} \node at (R\n.center) {$R$};
            \foreach \n in {1,2} \node at (2R\n.center) {$2R$};
        \end{circuitikz}
\end{document}