答案1
像这样:
\documentclass[border=1cm]{standalone}
\usepackage{tikz}
\usepackage{amsmath}
\begin{document}
\begin{tikzpicture}
\fill[gray!50](0,-0.2) rectangle +(2,0.4);
\fill[gray!50](4,-0.2) rectangle +(2,0.4);
\draw[thin,dashed](4,-1)--(4,1);
\draw[thick](0,0) -- (8,0) node[anchor=west]{$\Omega$};
\foreach \x/\txt in {0/{},2/25,4/100,6/400,8/{}} \draw[thick](\x,-0.2)--(\x,0.2) node[anchor=south,fill=white]{\txt};
\draw(0,-0.3)node[anchor=north west,inner sep=0pt]{$\underbrace{\rule{4cm}{0pt}}_{\text{FONT DE I}}$};
\draw(4,-0.3)node[anchor=north west,inner sep=0pt]{$\underbrace{\rule{4cm}{0pt}}_{\text{FONT DE V}}$};
\draw(0,2mm+\baselineskip)node[anchor=south west,inner sep=0pt]{$\overbrace{\rule{2cm}{0pt}}^{P>0'25\text{ W}}$};
\draw(4,2mm+\baselineskip)node[anchor=south west,inner sep=0pt]{$\overbrace{\rule{2cm}{0pt}}^{P>0'25\text{ W}}$};
\end{tikzpicture}
\end{document}