About phasor voltage and phasor current.

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Discussion Overview

The discussion revolves around the multiplication of phasor voltage, current, and impedance, particularly focusing on whether this multiplication can be represented as a dot or cross product. Participants explore the representation of these quantities as complex numbers and their implications in calculations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants propose that phasor voltage can be expressed as the product of phasor current and impedance, questioning the nature of this multiplication.
  • There is a suggestion that expressing impedance, current, and voltage as complex numbers may clarify the multiplication process.
  • One participant questions why complex multiplication does not correspond to dot or cross products, given that complex numbers can be viewed as vectors.
  • Another participant mentions using a two-by-two matrix representation for complex numbers and suggests that a dot product approach could yield voltage in matrix form, though they express uncertainty about the practicality of using a 2x1 vector.
  • A later reply encourages performing calculations in complex notation to explore the relationship to dot products or real-valued vectors.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of the multiplication of phasors, with multiple competing views on how to approach the calculations and the representation of complex numbers.

Contextual Notes

There are limitations regarding the assumptions made about the representation of complex numbers and the applicability of matrix forms in this context. The discussion does not resolve the complexities involved in the multiplication process.

Who May Find This Useful

This discussion may be of interest to those studying electrical engineering, particularly in understanding phasor analysis and complex number operations in circuit theory.

sabbir ahmed
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we know that phasor voltage, current and impedence can be represented by vector. we know phasor v is equals to the product of phasor i and impedence. the what is the process of multiplication? is it dot or cross product?
 
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I have no idea. Do you know how to multiply complex numbers? If I wanted the voltage as a function of impedence and current. I would express impedence, current and voltage as complex numbers.
 
Phrak said:
I have no idea. Do you know how to multiply complex numbers? If I wanted the voltage as a function of impedence and current. I would express impedence, current and voltage as complex numbers.

if complex number can be measured like a vector then why complex multiplication is not dot or cross?
 
sabbir ahmed said:
if complex number can be measured like a vector then why complex multiplication is not dot or cross?

Do the calculations in complex notation and see if you have can convert it to the dot product or real valued vectors.
 
The only way I've ever seen complex numbers in matrix form was like so:

[real -imag]
[imag real ]

So it's a two by two matrix, so if you input the impedance, and current into these equations and do the DOT-PRODUCT, you'll get the voltage in matrix form.

I don't think you can easily do it with a 2x1 vector though. It gets complicated and very difficult to keep track.

Try the matrix thing yourself. It's kind of need. I think this is a building block on SPICE programs, not sure though about that

--------------
Justin Coulston
justin.coulston@gmail.com
TheModernEngineer.blogspot.com
 

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