Sinusoidal sources and complex power

In summary, the complex conjugate of the current is used to compute apparent power in a given circuit because it is part of the formula I* times V, which is equivalent to I times Z. This is due to the relationship between current (I), impedance (Z), and voltage (V).
  • #1
d.arbitman
101
4
When calculating power in a given circuit, why is the complex conjugate of the current used to compute power?
 
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  • #2
darbitman,

When calculating power in a given circuit,

You mean apparent power, don't you?

why is the complex conjugate of the current used to compute power?

Easy, the apparent power is I^2 multiplied by Z, which equals I* times I times Z, which equals I* times V. I* is the conjugate of I, I^2 = I times I*, and I times Z = V .

Ratch
 
  • #3
Ratch said:
darbitman,



You mean apparent power, don't you?



Easy, the apparent power is I^2 multiplied by Z, which equals I* times I times Z, which equals I* times V. I* is the conjugate of I, I^2 = I times I*, and I times Z = V .

Ratch

I meant apparent power, sorry. And thank you for the explanation.
 

What is a sinusoidal source?

A sinusoidal source is a type of electrical source that produces a periodic, or repeating, signal that follows a sine wave pattern. It is commonly used in alternating current (AC) circuits and can be described using parameters such as amplitude, frequency, and phase.

What is complex power?

Complex power is a mathematical concept used to describe the combination of real power (which is the actual power used by a circuit) and reactive power (which is the power stored and released by a circuit). It is represented by a complex number and is also known as apparent power.

How is complex power calculated?

Complex power can be calculated using the formula S = P + jQ, where S is the complex power, P is the real power, and Q is the reactive power. It can also be calculated using the voltage and current in a circuit, using the formula S = VI*, where V is the voltage and I* is the complex conjugate of the current.

Why is complex power important?

Complex power is important because it helps us understand the behavior of AC circuits. By considering both real and reactive power, we can determine the efficiency of a circuit and identify any issues such as power factor and voltage drop. It is also essential in power system analysis and design.

What are some applications of sinusoidal sources and complex power?

Sinusoidal sources and complex power have various applications, including power generation, transmission, and distribution. They are also used in electrical machines, such as motors and generators, and in electronic devices, such as power supplies and inverters. In addition, they are crucial in renewable energy systems, such as wind and solar power, and in power quality monitoring and control.

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