Question

sqrt(-1) in EE

Answer 1

EE?

Answer 2

must be Electrical Engineering

Answer 3

Oh well... then I'm not aware....
Last I checked, we usually had as standard:
\[\Large i = \sqrt{-1}\]
^_^

Answer 4

aha, thanks :)

Answer 5

wait, maybe they mean notation. Wikipedia says (for all its worth) that in electrical engineering, the imaginary unit is instead
\[\Large j = \sqrt{-1}\]

Answer 6

yup just read that too, I'm diving into unknown waters here :d

Answer 7

The operator J which is used rather than "i" as "i" is used to indicate current. It comes into play with applications using "reactance" (both capacitive -j and inductive +j). The complex plane is used when calculating the "total" impedance of reactive circuits.

Answer 8

I didn't think imaginary numbers or complex numbers actually had applications ^_^

Answer 9

Yes, it comes into play when there is a phase difference in voltage and current. Phase difference is introduced by reactance. That is why there is "apparent" power (VAR) and real power (EI cos phase angle). Electric companies wish to maintain minimum phase difference between i and e. Industry tends to introduce inductive reactance due to the usually large "motor" loads. Power companies use capacitor banks to restore the power to real (or require manfucturer plants to install them)

Answer 10

There is some use of complex numbers in the "real" world lol.

Answer 11

I suppose the fact that \(\Large -j \cdot j = 1\) plays a role ?

Answer 12

Absolutely, that is why the attempts with the capacitor banks. I need to run, a retirement party is planned for a friend of mine.

Answer 13

:)