\documentclass{ppex}
\nonstopmode
\usepackage [basic,box,gate,ic,optics]{circ}
\pagestyle{empty}

\begin{document}
\ResetPreambleCommands
\ReadyForTheFray
\usepackage [basic,box,gate,ic,optics]{circ}
\begin{circuit}{0}
\.1 \- 1 r \nl\cc\R1 {R} h
\frompin .1 \- 3 l \- 2 d \<\nl\R9 {2R} v \- 10 d \.7
\frompin .7 \- 3 l \cc\U0 {} u
\frompin .1 \- 2 d \<\nl\cc\R2 {2\,R} v \nl\SW1 {} s U
\frompin SW1c \vtopin U0+ \.8
\frompin SW1o \vtopin U0- \.9
 \iffalse
\frompin R1r \- 1 r
\.2 \- 1 r \nl\cc\R3 {R} h
\frompin .2 \- 2 d \<\nl\cc\R4 {2\,R} v \nl\SW2 {} s u
\frompin SW2c \vtopin U0- \.10
\frompin SW2o \vtopin U0+ \.11
 \fi
\frompin R1r \- 1 r
\.3 \- 1 r \nl\cc\R5 {R} h
\frompin .3 \- 2 d \<\nl\cc\R6 {2\,R} v \nl\SW3 {} s u
\frompin SW3c \vtopin U0- \.12
\frompin SW3o \vtopin U0+ \.13

\frompin R5r \- 1 r
\.4 \- 2 r \nl\cc\R7 {R$_1$= 2R} h
\frompin .4 \- 2 d \<\nl\cc\R8 {2\,R} v \nl\SW4 {} s U
\frompin SW4c \vtopin U0+ \htopin U0+
\frompin SW4o \vtopin U0- \.15

\frompin R7r \- 1 r \nl\whatI1 {I} r
\- 1 r \.5 \- 1 r \nl\OV1 {} - {} {} {}
\frompin .5 \- 3 u \centerto OV1 \nl\cc\R10 {R$_2$} h
\frompin R10l \htopin .5
\atpin OV1O \.6 \vtopin R10r \htopin R10r
\frompin .6 \- 1 r \connection1 {$U_a$} r
\frompin OV1+ \- 1 l \- 3 d \<\nl\cc\R11 {R$_3$} v
\frompin R11d \vtopin .7 \.8 \GND1 \frompin .7 \htopin .8
\frompin .7 \- 3 l \cc\U0 {} u
\end{circuit}
\end{document}