| Re: Application of algebra |
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Group: rec.crafts.metalworking · Group Profile
Author: HawkeHawke Date: Jun 15, 2008 22:34
>> how do you imagine imaginary
>> numbers - positive and negative phasors and vectors - +j -j - I KNOW
>> they mean something, but its just chicken tracks to me.
>>
>> Andrew VK3BFA.
>>
>> And if I have stuffed up the cutting and quoting bit above and got the
>> names wrong - sorry, no offense meant.
>
>
> Don't worry about it. Just accept it.
>
> Don't let the name imaginary bother you. Use the term complex
> instead.
>
> With DC in the steady state, the power is Voltage times Current.
>
> With AC the power is the Voltage times the Current that is in phase
> with the voltage. P = E I cos theta. If theta is 45 degrees then Cos
> theta is 1/ 2^.5
>
> Now if you think of a 45, 45, 90 triangle , then the current that is
> in phase can be represented by one of the legs of the triangle. The
> total current is represented by the hypotenuse. So what is the other
> leg of the triangle? It is the current that is 90 degrees out of
> phase with the voltage. It is orthogonal to the in phase current.
> That is you can change the value without affecting the other leg
> ( you do affect the total current, but not the in phase current )
>
> Now if you can see that, then all that stuff about complex numbers is
> just a way to do the calculations instead of drawing triangles. Got
> two vectors you want to add. Just draw one and then draw the second
> with the beginning of it at the end of the first.
> Or you can break both vectors into two parts that are orthogonal and
> add the " real " parts and then add the "imaginary" parts.And you end
> up with the same total length and direction, but you did not have to
> draw the two vectors.
>
> I hope that is clear to you. It is to me.
>
> Dan
> AD7PI
Thanks for proving my original point far better than I ever could. What is
clear to you is completely incomprehensible to most of the rest of us. That
is the way it works. Six foot eight inch basketball players have no trouble
dunking either. They wouldn't be able to understand why you can't except
that you are lacking something they have. That's the way it is with math.
Those who can comprehend it have something the rest of us don't have. But I
learned long ago that the math guys were often very, very bad at all kinds
of other things and different ways of thinking. Only a very few lucky people
can comprehend higher math and do everything else well too. You don't want
to compete with those guys unless you happen to be one of them. It's like
the time I was watching a lecture on cable TV and it was an advanced
computer science class. I'm no dummy but I couldn't understand a thing the
teacher was saying. It was so far over my head it was a joke. But for the
people that can comprehend it that were in the class it made perfect sense.
It's a case of one having to know one's limitations, I guess.
Hawke
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