\documentclass[]{standalone}
\input{./tikzpreamble}

\begin{document}
\begin{circuitikz}[scale=2]

    \draw[color=black, thick]
    (-.8,3)
      % to [short, *-] (-.8,3)
      to [voltmeter, *-] (-.8,-.5)
      to [short, -*] (0,-.5)

    (-.2,1.45) node[left] {V$_\text{drop}$}

    (-1.7,.9) node[draw=black, fill=white, minimum height=2.8cm, minimum width=2cm, ultra thick] (pit) {\large PIT}
    (-1.7,3) to [short, -*] (pit.north) node[below, draw=black, minimum width=2cm] {V$_\text{O}$}
    (pit.south) node[above, draw=black, minimum width=2cm] {GND$_\text{O}$} to [short, *-] (-1.7,-1.2) 
    (-1.7,3)%  node[right] {V$_\text{ss}$ = 1.8V}
      to (0, 3)
      to [R, l={$R_0$}, v_>=$I_{ges}$, -] (0,1.5)
      to [nos, *-] (0,1)
      to [R, l={$R_1$}, v_>=$I_{ret}$, -] (0,-.5)
      to (0, -.8) node[draw=black, fill=white]{reticle}
      to [short, -] (0,-1.2)
      to [short, -] (-1.7, -1.2) %node[left] {GND}

    (0,1.5)
      to [] (.6,1.5)
      to [nos, *-] (.6,1)
      to [R, l={$R_1$}, -] (.6,-.5)
      to (.6, -.8) node[draw=black, fill=white]{reticle}
      to [short, -] (.6,-1.2)
      to [short, -*] (0, -1.2)
    
    (.6,1.5)
      to [] (1.2,1.5)
      to [nos, *-] (1.2,1)
      to [R, l={$R_1$}, -] (1.2,-.5)
      to (1.2, -.8) node[draw=black, fill=white]{reticle}
      to [short, -*] (1.2,-1.2)
      to [short, -*] (0.6, -1.2)

    (1.2, -1.2) to (1.5, -1.2) node[right]{\ldots}

    (1.2,1.5) to [] (1.5, 1.5) node[right]{\ldots};
\end{circuitikz}
\end{document}