# 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?

• I thought you guys used J or j? Jan 11, 2013 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. Jan 11, 2013 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? Jan 11, 2013 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. Jan 11, 2013 at 13:55
• Thank you, I will use capital iota Jan 11, 2013 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"} &;