Here are circuitikz diagrams illustrating potentiometric setups.
Basic potentiometric setup (battery E, current I, potentiometer R, voltmeter, points A/B/C with U_AC, U_CB, U):
\documentclass[border=5pt]{standalone}
\usepackage{circuitikz}
\newcommand{\voltmeter}{node[circle,draw]{{\color{black!70}\textbf{V}}}}
\newcommand{\amperemeter}{node[circle,draw]{{\color{black!70}\textbf{A}}}}
\begin{document}
\begin{circuitikz}
\draw [line width=1] (-1,0) --(-1,1) to[battery, l=$E$, i=$I$, invert, line width=0.5]
(-1,5) --(6,5)
to[potentiometer, l_=$R$] (6,2)
--(6,0)
--(-1,0);
\draw [line width=1] (6,3.5) -- (8,3.5);
\draw[line width = 1] (6,0) --(8,0) --(8,1.63);
\draw [line width=1](8,2) \voltmeter (8,3.5);
\draw [line width=1](8,3.5) --(8,2.37);
% Points
\draw (6,5) node[ right] {$A$};
\draw (6,0) node[above right] {$B$};
\draw (6,3.5) node[above right] {$C$};
\draw (6,5) node {$\bullet$};
\draw (6,0) node {$\bullet$};
\draw (6,3.5) node {$\bullet$};
% Flèches de tension
\draw[>=stealth,->, thick] (5.3,3.5) -- (5.3,4.8) node[midway,left] {$U_{AC}$};
\draw[>=stealth,->, thick] (5.3,0.3) -- (5.3,3.3) node[midway,left] {$U_{CB}$};
\draw[>=stealth,->, thick] (-1.9,0) -- (-1.9,5) node[midway,left] {$U$};
\end{circuitikz}
\end{document}
Potentiometric setup with a lamp (ammeter, voltmeter, lamp L):
\documentclass[border=5pt]{standalone}
\usepackage{circuitikz}
\newcommand{\voltmeter}{node[circle,draw]{{\color{black!70}\textbf{V}}}}
\newcommand{\amperemeter}{node[circle,draw]{{\color{black!70}\textbf{A}}}}
\tikzset{
pics/interruptor/.style={
code = {
\draw (0,0) -- (1,0);
\draw (2,0) -- (3,0);
\draw (1,0) -- (1.8,0.5);
\fill (1,0) circle (2pt);
\fill (2,0) circle (2pt);}}}
\begin{document}
\begin{circuitikz}
\draw [line width=1] (-1,-2) to[battery, l=$E$, invert, line width=0.5] (-1,5);
\draw [line width=1] (-1,5)
--(4,5)
to[potentiometer,line width=0.7] (4,2)
--(4,-2)
--(-1,-2);
\draw [line width=1] (4,3.5)
--(4.6,3.5);
\draw [line width=1] (5,3.5)
\amperemeter (5.5,3.5);
\draw [line width=1] (5.4,3.5)
-- (8,3.5);
\draw[line width = 1] (4,-2)
--(8,-2)
--(8,1.63);
\draw [line width=1](8,2)
\voltmeter (8,3.5);
\draw [line width=1](8,3.5)
--(8,2.37);
\draw [line width=1] (6,-2)
to [lamp, l_=$L$,i=$I'$, line width=0.7] (6,3)
--(6,3.5);
\draw (4,5) node[ right] {$A$};
\draw (4,-2) node[above right] {$B$};
\draw (4,3.5) node[above right] {$C$};
\draw (4,5) node {$\bullet$};
\draw (4,-2) node {$\bullet$};
\draw (4,3.5) node {$\bullet$};
\draw (6,-2) node {$\bullet$};
\draw (6,3.5) node {$\bullet$};
\draw[>=stealth,->, thick] (3.6,3.5) -- (3.6,4.8) node[midway,left] {$U_{AC}$};
\draw[>=stealth,->, thick] (5.4,-1.5) -- (5.4,3) node[midway,left] {$U_{L}$};
\draw[>=stealth,->, thick] (-1.9,-2) -- (-1.9,5) node[midway,left] {$U$};
\draw[>=stealth,->, thick] (3.6,-1.8) -- (3.6,3.3) node[midway,left] {$U_{CB}$};
\end{circuitikz}
\end{document}
Potentiometric setup with an added resistor R’:
\documentclass[border=5pt]{standalone}
\usepackage{circuitikz}
\newcommand{\voltmeter}{node[circle,draw]{{\color{black!70}\textbf{V}}}}
\newcommand{\amperemeter}{node[circle,draw]{{\color{black!70}\textbf{A}}}}
\tikzset{
pics/interruptor/.style={
code={
\draw (0,0) -- (1,0);
\draw (2,0) -- (3,0);
\draw (1,0) -- (1.8,0.5);
\fill (1,0) circle (2pt);
\fill (2,0) circle (2pt);}}}
\begin{document}
\begin{circuitikz}
\draw [line width=1] (-1,-2) to[battery, l=$E$, invert, line width=0.5] (-1,5);
\draw [line width=1] (-1,5)
--(4,5)
to[potentiometer,line width=0.7] (4,2)
--(4,-2)
--(-1,-2);
\draw [line width=1] (4,3.5)
--(4.6,3.5);
\draw [line width=1] (5,3.5)
\amperemeter (5.5,3.5);
\draw [line width=1] (5.4,3.5)
-- (8,3.5);
\draw[line width = 1] (4,-2)
--(8,-2)
--(8,1.63);
\draw [line width=1](8,2)
\voltmeter (8,3.5);
\draw [line width=1](8,3.5)
--(8,2.37);
\draw [line width=1] (6,-2)
to [resistor, l_=$R'$,i=$I'$, line width=0.7] (6,3)
--(6,3.5);
\draw (4,5) node[ right] {$A$};
\draw (4,-2) node[above right] {$B$};
\draw (4,3.5) node[above right] {$C$};
\draw (4,5) node {$\bullet$};
\draw (4,-2) node {$\bullet$};
\draw (4,3.5) node {$\bullet$};
\draw (6,-2) node {$\bullet$};
\draw (6,3.5) node {$\bullet$};
\draw[>=stealth,->, thick] (3.6,3.5) -- (3.6,4.8) node[midway,left] {$U_{AC}$};
\draw[>=stealth,->, thick] (5.5,-1.5) -- (5.5,3) node[midway,left] {$U'$};
\draw[>=stealth,->, thick] (-1.9,-2) -- (-1.9,5) node[midway,left] {$U$};
\draw[>=stealth,->, thick] (3.6,-1.8) -- (3.6,3.3) node[midway,left] {$U_{CB}$};
\end{circuitikz}
\end{document}
Potentiometric setup with a cell, galvanometer, switch, and rheostat (Pile, Ig, S1, Rh, R, U_g, U_R, U_Rh):
\documentclass[border=5pt]{standalone}
\usepackage{circuitikz}
\newcommand{\voltmeter}{node[circle,draw]{{\color{black!70}\textbf{V}}}}
\newcommand{\amperemeter}{node[circle,draw]{{\color{black!70}\textbf{A}}}}
\tikzset{
pics/interruptor/.style={
code={
\draw (0,0) -- (1,0);
\draw (2,0) -- (3,0);
\draw (1,0) -- (1.8,0.5);
\fill (1,0) circle (2pt);
\fill (2,0) circle (2pt);}}}
\begin{document}
\begin{circuitikz}
% Pile et interrupteur
\draw [line width=1] (-3,0) to[battery, l=$Pile$, i=$I_g$, line width=0.5] (7,0);
\pic[rotate=270, line width=1] at (7,0) {interruptor};
\node at (7.7,0.5) {$S_1$};
% Branche du bas avec Rh, R et ampèremètre
\draw [line width=1] (7,0) --(7,-1);%-- (7,-4)
\draw [line width=1] (7,-3)--(7,-7)--(5,-7)
to[variable resistor ,l_=$Rh$, line width = 0.5, invert] (4,-7)
to[ resistor, l_=$R$, line width = 0.5, invert] (-1.1,-7);
\draw[line width=1] (-1.5,-7) \amperemeter (-1,-7);
\draw[line width = 1] (-1.9,-7)--(-3,-7)--(-3,0);
% Voltmètre en parallèle sur R
\draw [line width=1] (5,0) -- (5,-3) -- (3.4,-3);
\draw [line width=1] (3,-3) \voltmeter (2.63,-3) -- (-3,-3);
% Flèches de tension
\draw[>=stealth,->, thick] (-2,1.2) -- (6,1.2) node[midway,above] {$U_{g}$};
\draw[>=stealth,->, thick] (-2.4,-6) -- (2.8,-6) node[midway,above] {$U_{R}$};
\draw[>=stealth,->, thick] (3.3,-5.8) -- (6.3,-5.8) node[midway,above] {$U_{Rh}$};
\end{circuitikz}
\end{document}
