What is the Purpose and Significance of Complex Numbers in Engineering?

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SUMMARY

Complex numbers are essential in engineering, particularly in communication and electrical engineering, where they facilitate the analysis of circuits and systems in the frequency domain. The real part of a complex number represents the magnitude of a quantity, while the imaginary part indicates the phase angle, crucial for understanding impedance in transmission lines and electrical machines. For example, in analyzing capacitors and inductors, complex numbers simplify the representation of sinusoidal signals, transforming differential equations into algebraic forms. The symbol "i" denotes the imaginary unit, allowing engineers to work with two-component problems effectively.

PREREQUISITES
  • Understanding of basic algebra and arithmetic operations
  • Familiarity with electrical engineering concepts, particularly impedance
  • Knowledge of sinusoidal signals and their properties
  • Basic grasp of vector mathematics and phase angles
NEXT STEPS
  • Explore the application of complex numbers in circuit analysis using the Laplace transform
  • Study the role of complex numbers in signal processing and frequency-domain analysis
  • Learn about impedance and its representation in complex form for capacitors and inductors
  • Investigate graphical representations of complex numbers and their applications in engineering
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Electrical engineers, communication engineers, students studying circuit analysis, and anyone interested in the application of complex numbers in engineering contexts.

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My question is about Complex number.
I can solve and calculate complex numbers. But i m still Unsure about the Concept of Complex number.
I have read many articles and they say that a symbol i is added to make the solutions possible.\

In communication engineering, as well as Electrical engineering, this number plays an important role.

Keeping this in mind, Tell me what does the real part and imaginary part of a Complex number shows with an example..Take capacitor or Inductor.
We have learned in primary classes about the Numbers with Fundamental Concepts.
Tell me the Fundamental Idea and Concept of Complex number in context to any application or Example so that the idea behind the number can be visualized properly.

We talk a lot about impedance in transmission lines and they all are in complex number,even in Electrical Machines, Transformer or Motors, I don't understand where actually the real and imaginary part lie? What does the Real part in practical as well as the imaginary part shows??
Can you Evaluate or Mark and show me from some observation ( or from graph ,a point ) practically and name it complex number with real and imaginory?

Saying so , Please share links,Flash Demonstration, so that i can easily understand this number fundamentally!

And why the real part and imaginoary part are added?? to combine a new number,? and how?
Justify with REASONS AND EXPLANATION
And since symbol "i" is imaginary , how one can translate the word imaginary?Even knowing the complex number hold a significant value in engineering?Does "i" have some transformation?
Thanks

Regards
 
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In EE complex numbers are convenient for doing ordinary algebra to solve two-component problems.

Analyzing circuits at a frequency S turns the differential equations of a circuit into algebraic ones. Laplace transform for example.

A complex number has a magnitude and a phase. A real number only has a magnitude so it's not easy to solve frequency-domain problems (where every system changes the amplitude and phase of the input but is still sinusoudal.)
 
Think of a number. Say, 150. What can you do with it? Not much! It's bigger than 149. Yawn.

Now if you wanted to convey information about the weight of your mother, simply saying "150" would be meaningless. 150 what? Tonnes? LOL, of course not -- you meant 150 kg, and that calls for a scalar quantity, which is simply the product of a numerical value and a physical unit.

But what about the situation where your mother is in free-fall after a parachute jump from a high-altitude balloon? How can we talk about the force that is acting on her body? Well, from the sound of her screaming, we know she's accelerating, and Newton's Second Law or whatever tells us Force = (mass * acceleration). But in what direction is she accelerating? Is she going up? Hell, no. She's going down. So the Force has a magnitude of m*a (measured in kg*m/s^2) and a downward direction. The Force is a vector!

Notice how we went from a simple number to a scalar, and finally to a vector, and how we were able to increase the amount of information along the way. A complex number is also a vector with a magnitude and a direction (or "phase angle") as any other vector. In the same way that the force vector allowed you to describe your mom in free-fall, complex numbers makes your life easier by, e.g., giving you a way to describe the how the phase of a electrical signal varies with time, etc.
 
Most likely this can only be answered by an "old timer". I am making measurements on an uA709 op amp (metal can). I would like to calculate the frequency rolloff curves (I can measure them). I assume the compensation is via the miller effect. To do the calculations I would need to know the gain of the transistors and the effective resistance seen at the compensation terminals, not including the values I put there. Anyone know those values?

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