# Using the symbol I for electrical current [duplicate]

I would like to use the I as a symbol for the electrical current. How can I redefine it, so it is not interpreted as the imaginary unity?

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## marked as duplicate by R. M.♦Apr 13 '13 at 17:13

I thought you guys used J or j? – cormullion Jan 11 '13 at 13:47
I would strongly recommend against doing so since complex numbers are fundamental in Mathematica. Instead, you should use some other symbol, which you can easily make print as "I" if you so wish. – Oleksandr R. Jan 11 '13 at 13:49
Yes, we use j for the imaginary unit, and i and I for currents. But if I use I for a current, mathematica interprets it as the imaginary unity. So, how can I get Mathematica to interpret I as my own symbol instead of the imaginary Unit? – Diegos Jan 11 '13 at 13:54
@Diegos Do you find using \[CapitalIota] unacceptable? If you really want to use raw I I'll show you how, but using it is against my better judgement. – Mr.Wizard Jan 11 '13 at 13:55
Thank you, I will use capital iota – Diegos Jan 11 '13 at 14:17

The short answer is don't do it. Really, it's just not a good idea. You can use other symbols, such as \[CapitalIota] which looks almost exactly like I and is entered with EscIEsc.
If you're really determined you could substitute symbols using $PreRead and MakeBoxes but again I don't recommend it. For example: MakeBoxes[I, _] := "\[ImaginaryJ]" MakeBoxes[currentI, _] := "I"$PreRead = # /. {"I" -> "currentI", "j" -> "I"} &;