\documentclass[tikz, margin=15px]{standalone}
\usepackage{color,graphicx,circuitikz}
\usepackage[load-configurations=version-1]{siunitx}
\usetikzlibrary{arrows}
\begin{document}
 
\begin{circuitikz}[american, very thick]
\draw
 (0,4) to (8,4) to [cV, l_=\huge{$3i_x$}](8,7)
 (0,4) to [V, l=\huge{$V_\textrm{s}$}] (0,7)
 (0,7) to [R, l=\huge{$R_1$}](4,7) to [R, l=\huge{$R_2$}](8,7)
 (4,4) to [R, l_=\huge{$R_3$}, i^<=\huge{$i_x$}](4,7)
 {(2,5.5) node {\huge{\color{red}{$i_1$}}} (6,5.5) node {\huge{\color{red}{$i_2$}}}};
 
 \draw[very thick, red, <-, >=triangle 45] (2.5,4.6) arc (-60:240:1);
 
 \draw[very thick, red, <-, >=triangle 45] (6.9,4.6) arc (-60:240:1);
;\end{circuitikz}
 
\end{document}