CircuitTiKz lines not straight

Question

I made a schematic using following code:

\begin{circuitikz}
    \draw
        (0,0) node[op amp, scale=2] (opamp) {}
        (opamp.+) -- (-2.38,-3) node[ground] {}
        (opamp.+) node[left, above] {$u_+$}
        (opamp.-) node[left, below] {$u_-$}
        (opamp.out) to[short, -*](4,0) node[right] {$u_{izl}$}
        (opamp.-) to[R, label=$R_1$, i<=$i_1$, *-*] (-8, 1) node[left] {$u_{ul}$}
        (opamp.-) to[short] (-2.4,4) {}
        (-2.4, 4) to[R, label=$R_2$, i>=$i_2$] (3,4) {}
        (3,4) to[short, -*] (3,0)
        (opamp.up) to[short, -*] (-0.17,2.5) {}
        (opamp.down) to[short, -*] (-0.17,-2.5) {}
        (4,0) to[] (4,0) {}
        ;
\end{circuitikz}

However some of the lines on it aren't straight like these ones:

I tried changing coordinates but I can't get it right. Is there an easier way of doing this?

Answer 1

You can assign node names to the nodes that will form the intersection, and then use the syntax to[short] (u1|-u2). This could have a very precise outcome, but due to how the structured in circuitikz, I had to do some manual tweaking for the other edge.

In any case, the line is straight now.

Output

Code

\documentclass[tikz, margin=10pt]{standalone}
\usepackage[europeanresistors]{circuitikz}

\begin{document}
\begin{circuitikz}
    \draw
        (0,0) node[op amp, scale=2] (opamp) {}
        (opamp.+) -- (-2.38,-3) node[ground] {}
        (opamp.+) node[left, above] {$u_+$}
        (opamp.-) node[left, below] (u1) {$u_-$}
        (opamp.out) to[short, -*](4,0) node[right] {$u_{izl}$}
        (opamp.-) to[R, label=$R_1$, i<=$i_1$, *-*] (-8, 1) node[left] {$u_{ul}$}
        (-2.38,4) to[R, label=$R_2$, i>=$i_2$] (3,4) node (u2) {}
        (opamp.-) to[short] (u1|-u2) {}
        (3,4) to[short, -*] (3,0)
        (opamp.up) to[short, -*] (-0.17,2.5) {}
        (opamp.down) to[short, -*] (-0.17,-2.5) {}
        (4,0) to[] (4,0) {}
        ;
\end{circuitikz}
\end{document}