\documentclass[tikz,margin=3.14mm]{standalone}
\usetikzlibrary{arrows.meta,decorations.pathmorphing}
\begin{document}
\begin{tikzpicture}
\draw (0,-3) -- (0,3) node[left]{$v_{B1}$};
\draw (0,0) node[left]{0} -- (10,0) node[below left]{$t$};
\draw[very thick] (0,0.1) -- ++(1,0) -- ++(0,-1) coordinate (x1) -- ++(6,0)
coordinate (x2) -- ++(0,1) -- ++(2.5,0);
\draw[{Straight Barb[length=0pt,width=4mm] Latex[]}-{Latex[] Straight Barb[length=0pt,width=4mm]}]
(1,0.5) -- (7,0.5) node[midway,fill=white]{$T_g$};
\node (VBE) at (0.5,1) {$V_{BE}$};
\draw[-{Latex[]}] (VBE) -- (0.5,0.1);
\draw[-{Latex[]}] (0.5,-0.7) -- (0.5,-0.1);
%
\begin{scope}[yshift=-8.5cm]
\draw (0,-1) -- (0,5) node[left]{$\ell_{C1}$};
\draw (0,0) node[left]{0} -- (10,0) node[below left]{$t$};
\draw[very thick] (0,1) node[left]{$\displaystyle\approx\frac{V_{CC}}{R}$} -- ++(1,0)
-- ++(0,-1) coordinate (y1) -- ++(6,0) -- ++(0,3) coordinate (y2) -- ++(1,0) --
++(0,-2) coordinate (y3) -- ++(1.5,0);
\node (ICBO) at (2,1) {$I_{CBO}\approx0$};
\draw[-{Latex[]}] (ICBO) -- (2,0);
\draw[-{Latex[]}] (2,-0.7) -- (2,0);
\draw (5,3) -- (7,3);
\draw[{Latex[]}-{Latex[]}] (6,3) -- (6,0) node[midway,fill=white]{$\displaystyle
\frac{h_{FC}V_{CC}}{R_C}$};
\draw[thick] (11,3) -- (12,3) (11,1) -- (12,1);
\draw[thick,decorate,decoration={zigzag,pre length=5mm,post length=5mm,segment
length=5mm,amplitude=2.5mm}] (12,3) -- (12,1) node[midway,left=3pt] {$R_i$};
\end{scope}
%
\begin{scope}[yshift=-13cm]
\draw (0,-3) -- (0,3) node[left]{$v_0$};
\draw (0,0) node[left]{0} -- (10,0) node[below left]{$t$};
\draw[very thick] (0,0) -- ++(1,0)
coordinate (z1) -- ++(4,3) coordinate (z4) -- ++(2,0) coordinate (z2) -- ++(1,-3)
coordinate (z3) -- ++(1.5,0);
\draw[{Latex[]}-{Latex[]}] (6,3) -- (6,0) node[midway,fill=white]{$V_{CC}$};
\draw (z1 |-0,0) -- ++ (0,-3) coordinate[pos=1/6] (l1) coordinate[pos=1/2] (l2)
coordinate[pos=5/6] (l3);
\draw (z3 |- 0,0) -- ++(0,-3) coordinate[pos=5/6] (r3);
\draw (z4 |- 0,0) -- ++(0,-1) coordinate[pos=1/2] (m1);
\draw (z2 |- 0,0) -- ++(0,-2) coordinate[pos=3/4] (m2);
\draw[{Latex[]}-{Latex[]}] (l1) -- (m1) node[midway,fill=white]{$T_*$};
\draw[{Latex[]}-{Latex[]}] (l2) -- (m2) node[midway,fill=white]{$T_g$};
\draw[{Latex[]}-{Latex[]}] (l3) -- (r3) node[midway,fill=white]{$T$};
\draw[dashed] (z4) -- (z4 |- 0,0);
\draw[dashed] (x2) -- (z2 |- 0,0);
\end{scope}
\draw[dashed] (x1) -- (z1) node[pos=0.1,fill=white] {$t=0$};
\draw[dashed] (y3) -- (z3);
\end{tikzpicture}
\end{document}
![在此处输入图片描述](https://i.stack.imgur.com/PaaMV.png)