Imaginary component

Discussion in 'General Electronics Chat' started by aamirali, Sep 3, 2012.

Feb 2, 2012
415
2
In real world there is only real parts.
Then why imaginary is included, I never got this. What its use. Finally even answer is calculated by this.

Like s=jw.
+j,-j etc

2. MrChips Moderator

Oct 2, 2009
19,044
6,117
"Imaginary" is not imaginary. It is real, i.e. (x + iy) exist in the real world.
The word "imaginary" in this context as a mathematical construct is an unfortunate usage of the word.

So just ignore the usual meaning of the word "imaginary" and get on with it.
On the same note, negative frequencies are real.

#12 likes this.
3. Papabravo Expert

Feb 24, 2006
12,212
2,697
In many areas of electronics there are two things we want to keep track of, magnitude and phase. It might be easier on your cognitive sensibilities to rename the imaginary unit as a rotation operator. Instead of starting with j=SQRT(-1) think of multiplication by j as a rotation by 90 degrees. On top of that, four successive rotations returns you to the original position.

Finally the algebra of complex numbers matches the behavior of AC electric circuits which require you to keep track of both magnitude and phase. That is all the justification you should require.

nobody0608 likes this.
4. ErnieM AAC Fanatic!

Apr 24, 2011
7,986
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Do keep trying to get this as it IS useful.

It's a mathematical term, and like most things mathematical they have no direct connection with reality.

Don't believe me? Just try to make 1/2 of a piece of paper.

No matter how carefully you measure and cut it you always end up with two pieces of paper, just smaller then the one you started with.

5. bountyhunter Well-Known Member

Sep 7, 2009
2,498
512
It sure is. They should have gotten a better name.

It is also referred to as the "complex" component which is a better name than imaginary..