使用 TiKz 绘制“光电二极管”符号

Question

在文献中，光电二极管通常被描绘成一个部分被矩形条“隐藏”的圆圈。如何使用 TiKz 绘制它？

到目前为止，我使用clip“隐藏”圆的一部分。然后，我叠加一个矩形。这种方法的问题在于它只是掩盖了输出（即，生成的 PDF 仍然描述了一个完整的圆）。

\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\clip (0,0) rectangle (10mm,10mm);
\draw[inner color=orange!20, outer color=orange, draw, very thick]  (2.5mm,5mm) circle (4mm);
\draw[fill] (0,0) rectangle (1.2mm,10mm);
\end{tikzpicture}
\end{document}

Answer 1

利用\pic：

\documentclass[border=10pt]{standalone}
\usepackage{tikz}

\tikzset{
    pics/photo diode/.style={
        code={
            \tikzset{photo diode/.cd, #1}
            \path[photo diode/bulb]
                ({-sqrt(3)*0.225},0) 
                arc[start angle=210, end angle=-30, radius=0.45]
                -- cycle;
            \path[photo diode/base] (-0.5,0) -- (0.5,0);
            \coordinate (-north) at (0,0.675);
            \coordinate (-south) at (0,0);
        }
    },
    photo diode/base/.style={
        draw,
        line width=4pt
    },
    photo diode/bulb/.style={
        draw,
        ball color=orange
    }
}

\begin{document}
\begin{tikzpicture}

\pic (P) at (0,0) {photo diode};

\pic[red] (Q) at (2,0) {photo diode={
    bulb/.append style={ball color=green}
}};

\draw (P-south) -- ++(0,-0.5) -| (Q-south);

\end{tikzpicture}
\end{document}

---

编辑以精确定位锚点坐标（感谢 Sebastiano）：

\documentclass[border=10pt]{standalone}
\usepackage{tikz}

\tikzset{
    pics/photo diode/.style={
        code={
            \tikzset{photo diode/.cd, #1}
            \path[photo diode/bulb]
                ({-sqrt(3)*0.225},0) 
                arc[start angle=210, end angle=-30, radius=0.45]
                coordinate[midway, yshift={0.5*\pgflinewidth}] (-north);
            \path[photo diode/base] (-0.5,0) -- (0.5,0)
                coordinate[midway, yshift={-0.5*\pgflinewidth}] (-south);
        }
    },
    photo diode/base/.style={
        draw,
        line width=4pt
    },
    photo diode/bulb/.style={
        draw,
        ball color=orange
    }
}

\begin{document}
\begin{tikzpicture}

\pic (P) at (0,0) {photo diode};

\pic[red] (Q) at (2,0) {photo diode={
    bulb/.append style={ball color=green}
}};

\draw (P-south) -- ++(0,-0.5) -| (Q-south);

\end{tikzpicture}
\end{document}