Re: Imagine i , j, (-1)^-2

bz wrote: 
"Paul B. Andersen" <paul.b.andersen@xxxxxxxxxxxxxxxx> wrote in news:d8d0lo
$lj2$1@xxxxxxxxxxxxxxxx:

Sue wrote: 
The null co-ordinates of Minkowski space are as just as unreal
as reactive power and stems from the same use of imaginary time.


This is meaningless babble.
"Reactive power" is as real as any power, and it doesn't
stem from the non existing "imaginary time".


Only the portions of current and voltage IN PHASE WITH EACH OTHER represent actual power. 

So what is "actual power" as opposed to "not actual power"?
The _active_ power is the electric power that flows into
the load and doesn't come back.
The reactive power is the power that flows back and forth
between the supply and load. It is stored in the load
for a part of the period.

My point was that it doesn't make sense to call
the reactive power "unreal" (or "imaginary").

Inductors and capacitors, each, shift the phase of the current wrt the voltage by an angle of 90 degrees, but in opposite directions.

So, a circuit consisting of only inductors and/or capacitors will not use any power. 

Of course it won't "use" power it in the sense that it dissipates it.
But real power will flow back and forth between the LC-circuit
and an attached AC-supply.
That the mean power is zero doesn't mean there is no power.

Let us look at a concrete electric circuit; an inductor L in
series with a resistor R.


The math does not require any imaginary numbers if you work with magnitudes and phase angles. 

Do you mean that the math doesn't require the use of complex numbers?
Of course it doesn't.


Conversion of the polar form to rectangular form just makes vector addition easier, but there is no need to call the reactive axis in the rectangular form 'imaginary', it is just done for convenience. 

I am not sure what you are trying to say.
But my very point was that using complex numbers is done
for convenience only, and that doesn't make any physical entity
- like power or time - "imaginary".

My bottom line was:
 A physical entity is always real.
 Both active and reactive power is real power.
 That complex numbers are used in the mathematical
 apparatus used to calculate the physical entities
 does not mean that there is anything imaginary about
 the physical entities.

Paul

.

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