Solenoid or coil.
Edit and compile if you like:
% Author: Izaak Neutelings (June 2018)\documentclass[border=3pt,tikz]{standalone}\tikzset{>=latex} % for LaTeX arrow head\usetikzlibrary{calc}\usetikzlibrary{patterns,snakes}\begin{document}\begin{tikzpicture}[scale=1]\def\R{0.8}\def\A{11} % amplitude\def\s{6} % coil segment length\def\L{8} % coil length\def\a{0.5} % coil segment aspect\def\dy{0.9} % vertical shift\def\dx{0.2} % horizontal shift\draw[snake=coil,thick,segment amplitude=2*\A,segment length=\s,segment aspect=\a](0,0) -- (\L,0);\draw[<->,shorten >=5](0,\dy) -- (\L,\dy) node[midway,above] {length $\ell$};\draw[snake=brace,mirror snake,segment amplitude=3](0,-\dy) -- (\L,-\dy) node[midway,below=1] {$N$ turns};\draw[-,thick](\L,0) -- (1.01*\L,0); % coil extension\draw[<->](-\dx,0) -- (-\dx,\R) node[midway,left=6] {$R$};\end{tikzpicture}\end{document}
Click to download: solenoid.tex • solenoid.pdf
Open in Overleaf: solenoid.tex