16

The symbol Voltampere VA should be printed without space between V and A, is there a way to correct that with siunitx?

 \documentclass{article}
 \usepackage{siunitx}
    \begin{document}
    \SI{10}{\volt\ampere}

    10 VA
  \end{document}

enter image description here

Penbeuz
  • 1,669
  • 6
    There is no difference between the multiplication here and in other cases (e.g. \volt\metre or \kilogram\ampere). Dealing with the kerning is a bit of a problem, but there certainly should be a space if you use one in other cases. – Joseph Wright Jun 07 '13 at 10:09
  • 2
    @JosephWright: Voltampere is a special unit for apparent power and so there shouldn't be a space. A normal engineer only writes \watt :-) – Marco Daniel Jun 07 '13 at 10:16
  • 6
    @MarcoDaniel Perhaps 'in use', but from a unit-analysis POV it's two units (one base, one named). As you indicate in your answer, the way to deal with these 'special cases' is to define a custom unit (see \kWh for example). – Joseph Wright Jun 07 '13 at 10:18
  • 3
    There's no symbol "voltampere" in the SI. – Luigi Jun 07 '13 at 10:19
  • 2
    I (and ISO 80000-6 sec.6-57a) agree with @JosephWright: it's correct to write \volt\ampere – Luigi Jun 07 '13 at 10:24
  • @Luigi: Please be aware. In Germany we have DIN1301 which specifies your ISO. However \volt\ampere indicates two units whereby Volt-ampere is only one unit. (This is my understanding) – Marco Daniel Jun 07 '13 at 10:40

2 Answers2

15

You can define your own units by \DeclareSIUnit. In your case I suggest:

\documentclass{article}
\usepackage{siunitx}
\DeclareSIUnit \voltampere { VA } %apparent power 
\DeclareSIUnit \var { var } %volt-ampere reactive - idle power 
\begin{document}
    \SI{10}{\voltampere}
\end{document}

I changed the document class from minimal to article. The drawbacks of the document class are described here: Why should the minimal class be avoided?

Community
  • 1
Marco Daniel
  • 95,681
  • 1
    @doncherry: Changed. – Marco Daniel Jun 07 '13 at 11:45
  • 1
    At least in my case, Debian with texlive & texlive-science, I get to large of a space with this definition. It should be \DeclareSIUnit \voltampere {VA} %apparent power. Single spaces does matter. – evading Jan 28 '14 at 08:17
1

I had the same problem with TWh having a space between TW and h. To solve this I add an additional curly bracket at \tera\watt\hour:

\newcommand{\TWh}[1]{\SI{#1}{{\tera\watt\hour}}}

instead of 

\newcommand{\TWh}[1]{\SI{#1}{\tera\watt\hour}}
Phelype Oleinik
  • 70,814
JohPel
  • 11