How to make bigger the contour integral symbol [closed]

Question

Someone knows if the circle of the integral can be bigger?

Answer 1

The circle is part of the character, like the top of an 8 so the correct answer is that you are supposed to pick a font you like then trust the font designer. However this being TeX there are various circles available that could be abused.

\documentclass{article}
\usepackage{amsmath}
\newcommand\myoint{\mathop{\begin{picture}(0,0)\put(5,3){\circle{7}}\end{picture}{\int}}}
\begin{document}

\[ \oint\limits_C f(z) + \myoint\limits_C f(z)  \]

\end{document}