Krdytkyu

I would like to change the size of a simple logic gate

begin{circuitikz} draw

(0,0) node[and port] () {};

end{circuitikz}

The output is:

How can I control the size of the ouptut?

Welcome to TeX.SE! As usual in this kind of business with scale=<factor>.

documentclass{article}

usepackage{circuitikz} 

begin{document}

begin{circuitikz} 

draw (0,0) node[and port,scale=3] (n) {};

end{circuitikz}

end{document}

You can change the height and width of circuitikz components locally or globally using ctikzset.

(Inspired from this answer)

Doing it locally

documentclass[border=3mm]{standalone}

usepackage{circuitikz}

begin{document}

begin{circuitikz} draw

(0,0) node[and port] () {};

draw

pgfextra{ctikzset{tripoles/american and port/width=.55,

                        tripoles/american and port/height=.4}}

(0,-1.5) node[and port] () {};

draw

pgfextra{ctikzset{tripoles/american and port/width=.3,

                        tripoles/american and port/height=.2}}

(0,-2.5) node[and port] () {};

end{circuitikz}

end{document}

Doing it globally

documentclass[border=3mm]{standalone}

usepackage{circuitikz}

begin{document}

ctikzset{tripoles/american and port/width=.55,tripoles/american and port/height=.4}

begin{circuitikz}

draw (0,0) node[and port] () {};

draw (0,-1) node[or port](){};

draw (0,-2) node[and port] () {};

end{circuitikz}

end{document}