\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
	(8,7) to (8,4) to (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 [I, l_=\huge{$I_\textrm{s}$}](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}