Example: Logic circuits library

% Logic circuits library
% Authors: Juergen Werber and Christoph Bartoschek
\documentclass{article}

\usepackage{tikz}
% load circuits library
\usetikzlibrary{circuits}
\begin{document}



\begin{tikzpicture}[scale=0.5,cktbaselength=0.5pt]
\draw (6,0) node[nand2ni,anchor=tip,draw] (n4) {}
      (n4.z) -- +(0mm,-5mm)
      (n4.b) |- ++(10mm,2mm) -- ++(0mm,2mm)
      node[and2in,anchor=z,draw,fill=gray] (n3) {}
      (n4.a) |- ++(-10mm,2mm) -- ++(0mm,2mm)
      node[or3nni,anchor=tip,draw] (n2) {}
      (n3.b) -- +(0mm,5mm) node[above] {$i_5$}
      (n3.a) |- ++(-5mm,2mm)
      coordinate (p) -- +(0mm,5mm) node[above] {$i_4$}
      (n2.c) |- (p)
      (n2.b) |- ++(6mm,12mm) -- +(0mm,5mm) node[above] {$i_3$}
      (n2.a) -- +(0mm,8mm)
      node[and2,anchor=tip,draw] (n1) {}
      (n1.b) -- +(0mm,5mm) node[above] {$i_2$}
      (n1.a) -- +(0mm,5mm) node[above] {$i_1$};
\end{tikzpicture}
%
% Define a few helper macros to save typing
% The \spacer macro inserts a dummy node and defines the t (top) and
% b (bottom) coordinates. t and b are used to align the pins
\newcommand\spacer{%
\node[anchor=south,minimum height=1cm,inner sep=0pt, outer sep=0pt] (tmp) {};%
\path (tmp.north) coordinate (t) (tmp.south) coordinate (b);%
}
% Draw connecting pins. Note the use of the t and b coordinates defined
% in the \spacer macro
\newcommand\drawpins[1]{%
\draw (#1.a) -- (t -| #1.a)
      (#1.b) -- (t -| #1.b)
      (#1.z) -- (b -| #1.z);
}
% Draw pins for a logic gate with tree inputs
\newcommand\drawpinsiii[1]{%
\draw (#1.a) -- (t -| #1.a)
      (#1.b) -- (t -| #1.b)
      (#1.c) -- (t -| #1.c)
      (#1.z) -- (b -| #1.z);
}
%
\begin{tikzpicture}[scale=0.5,cktbaselength=0.5pt,baseline]
\tikzstyle{gate} = [draw,anchor=center,yshift=5mm]
\tikzstyle{ann} = [below,font=\small\tt]
\matrix[column sep=0.5cm] (circuit shapes) {
    % Use the first column to place a dummy spacer node
    \spacer &[-0.5cm] % remove column spacing
    \node[and2,gate] (N10) {} node[ann] {and2};\drawpins{N10} &
    \node[and2in,gate] (N20) {} node[ann] {and2in};\drawpins{N20} &
    \node[and2ni,gate] (N30) {} node[ann] {and2ni};\drawpins{N30} &
    \node[and2ii,gate] (N40) {} node[ann] {and2ii};\drawpins{N40} \\
    \spacer &
    \node[nand2,gate] (N11) {} node[ann] {nand2};\drawpins{N11} &
    \node[nand2in,gate] (N21) {} node[ann] {nand2in};\drawpins{N21} &
    \node[nand2ni,gate] (N31) {} node[ann] {nand2ni};\drawpins{N31} &
    \node[nand2ii,gate] (N41) {} node[ann] {nand2ii};\drawpins{N41} \\
    \spacer &
    \node[or2,gate] (N12) {} node[ann] {or2};\drawpins{N12} &
    \node[or2in,gate] (N22) {} node[ann] {or2in};\drawpins{N22} &
    \node[or2ni,gate] (N32) {} node[ann] {or2ni};\drawpins{N32} &
    \node[or2ii,gate] (N42) {} node[ann] {or2ii};\drawpins{N42} \\
    \spacer &
    \node[nor2,gate] (N13) {} node[ann] {nor2};\drawpins{N13} &
    \node[nor2in,gate] (N23) {} node[ann] {nor2in};\drawpins{N23} &
    \node[nor2ni,gate] (N33) {} node[ann] {nor2ni};\drawpins{N33} &
    \node[nor2ii,gate] (N43) {} node[ann] {nor2ii};\drawpins{N43} \\
    \spacer &
    \node[or3,gate] (N14) {} node[ann] {or3};\drawpinsiii{N14} &
    \node[nor3iii,gate] (N24) {} node[ann] {nor3iii};\drawpinsiii{N24} &
    \node[or3nni,gate] (N34) {} node[ann] {or3nni};\drawpinsiii{N34} \\
    \spacer &
    \node[buffer,gate] (buf) {} node[ann] {buffer};
    \draw (buf.z) -- (buf.z |- b)
          (buf.a) -- (buf.a |- t); &
    \node[inverter,gate] (inv) {} node[ann] {inverter};
    \draw (inv.z) -- (inv.z |- b)
          (inv.a) -- (inv.a |- t); \\
};%
\node[above] at (circuit shapes.north) {Circuit node shapes};%
\end{tikzpicture}%


\end{document}