vertical spacing in one equation (not align)

Question

\begin{equation}
I_D=\frac{I_{sc_n}+K_i\Delta T}{exp\left(\frac{V_{oc_n}+K_v\Delta T}{nN_sV_t}\right)}
\end{equation}

That's my equation and here's its appearance

I think I can change the vertical spacing in the exp part. Because it looks like frac line touches the N and V in the document. But I don't know how.

unrelated to vertical space but use \exp (never use math italic for multi-letter identifiers it is designed to separate the letters so it looks like e times x times p (for same reason use \mathrm{sc} and \mathrm{oc}) — David Carlisle, Apr 28 '18 at 08:43
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score 4 · Answer 1 · answered Apr 28 '18 at 08:51

Common advice is to insert a \mathstrut, which is an invisible construct of zero width and vertical dimensions like a parenthesis. But that is not tall enough to do the trick here. You could insert a strut of your own making, i.e., a zero width rule of suitable height, into the denominator, but that is a bit error prone. So you could pick up a trick from an old answer of mine:

\documentclass{article}
\makeatletter
\newcommand{\raisemath}[1]{\mathpalette{\raisem@th{#1}}}
\newcommand{\raisem@th}[3]{\raisebox{#1}{$#2#3$}}
\makeatother
\begin{document}
\begin{equation}
I_D=\frac{I_{sc_n}+K_i\Delta T}{\exp\left(\frac{V_{oc_n}+K_v\Delta
      T}{\raisemath{-1pt}{nN_sV_t}}\right)}
\end{equation}
\end{document}

(Incidentally, use \exp for the exponential function.)

Or, instead of writing \mathstrut, write ^{\mathstrut}. – Mico Apr 28 '18 at 08:56 — Mico, Apr 28 '18 at 08:56
@Mico Clever. I didn't think of that. – Harald Hanche-Olsen Apr 28 '18 at 09:02 — Harald Hanche-Olsen, Apr 28 '18 at 09:02

score 3 · Answer 2 · answered Apr 28 '18 at 08:52

When you nest fractions like that, they get "squeezed". Maybe \dfrac is what you want?

\documentclass{article}
\usepackage{amsmath}
\begin{document}
  \[ I_D=\frac{I_{sc_n}+K_i\Delta T}{\exp\left(\dfrac{V_{oc_n}+K_v\Delta T}{nN_sV_t}\right)} \]
\end{document}

$\dfrac in \exp - result$

Bernard · Answer 3 · 2018-04-28T09:40:38.153

You can use the \mfrac (medium-sized fraction) from nccmath, which looks better anyway in nested fraction, with or without a \mathstrut, or \cfrac with the pair \biggl(...\biggr) in the place of \left(...\right). Compare:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath, nccmath}

 \begin{document}

\begin{equation}
I_D=\frac{I_{sc_n}+K_i\Delta T}{\exp\left(\frac{V_{oc_n}+K_v\Delta T}{nN_sV_t}\right)}
\end{equation}

\begin{equation}
I_D=\frac{I_{sc_n}+K_i\Delta T}{\exp\left(\mfrac{V_{oc_n}+K_v\Delta T}{nN_sV_t}\right)}
\end{equation}

\begin{equation}
I_D=\frac{I_{sc_n}+K_i\Delta T}{\exp\left(\mfrac{V_{oc_n}+K_v\Delta T}{nN_sV_t}\right)^{\mathstrut}}
\end{equation}

\begin{equation}
I_D=\frac{I_{sc_n}+K_i\Delta T}{\exp\biggl(\cfrac{V_{oc_n}+K_v\Delta T}{nN_sV_t}\biggr)}
\end{equation}

\begin{equation}
I_D=\frac{I_{sc_n}+K_i\Delta T}{\exp\left(\cfrac{V_{oc_n}+K_v\Delta T}{nN_sV_t}\right)}
\end{equation}
 \end{document}

Oh! yes. I didn't check where the cursor was when I inserted the image. Thanks for pointing it! — Bernard, Apr 28 '18 at 09:42

score 2 · Answer 4 · answered Apr 28 '18 at 09:05

Another solution would consist of not using \frac in the denominator and, instead, using inline-fraction notation. A benefit of taking this approach is that the symbols and letters won't be so tiny.

\documentclass{article}
\begin{document}
\begin{equation}
I_D=\frac{I_{sc_n}+K_i\Delta T}{%
\exp[(V_{oc_n}+K_v\Delta T)/(nN_sV_t)]}
\end{equation}
\end{document}

vertical spacing in one equation (not align)

4 Answers4