I'd like to customize the math symbol "evaluated at". If I use the code:
\documentclass[11pt]{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
\frac{d}{dt} \left( i_{O_L} \Bigr|_{O_G} \right) =
\end{equation*}
\begin{equation*}
\frac{d}{dt} \left( i_{O_L} \Bigg\rvert_{O_G} \right) =
\end{equation*}
\end{document}
In the first case the vertical bar is too small. In the second case the vertical bar grows up in both directions up and down. I'm wondering if it's possible to grow up the bar only below. For example (i want a thin vertical bar, in fugure it is not so thin):
EDIT:
Thank you so much for your time.