How Do You Calculate Apparent and Reactive Power in AC Circuits?

  • Context: Engineering 
  • Thread starter Thread starter charger9198
  • Start date Start date
  • Tags Tags
    Ac Ac circuits Circuits
Click For Summary

Discussion Overview

The discussion revolves around calculating apparent and reactive power in AC circuits, specifically focusing on a circuit with a given power factor and power dissipation. Participants explore various methods to compute apparent power, reactive power, current, and impedance, while addressing potential errors and clarifying concepts related to complex numbers in electrical engineering.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant calculates apparent power using the formula S = P/pf, arriving at approximately 520.83 VA.
  • Reactive power is computed using the formula VAR = SQRT(S^2 - P^2), yielding around 361.44 VAR.
  • Another participant questions the method used to determine total impedance, suggesting that impedance has real and imaginary components that should be considered.
  • There is a discussion on the phase angle, with some participants calculating it in radians while others prefer degrees, leading to confusion about the representation of the angle.
  • Participants explore the representation of complex current and impedance, with one participant attempting to clarify how to retain real and imaginary components in their calculations.
  • There is a debate on whether the impedance should be calculated as Vs/I, with some suggesting that the presence of inductance or capacitance would increase the impedance beyond the resistance value.
  • Complex arithmetic is discussed, with participants expressing difficulty in understanding how to manipulate complex numbers for impedance calculations.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method for calculating impedance and the handling of complex numbers. There are multiple competing views on how to approach the calculations, and some participants express confusion about the underlying concepts.

Contextual Notes

Participants mention limitations in their course materials regarding complex arithmetic, indicating that some of the methods discussed may not align with their current understanding or educational resources.

  • #61
gneill said:
Yes, that will work.

Is it correct to assume that the current value is the same throughout the circuit ? or would you obtain different value i.e. across the resistor
 
Physics news on Phys.org
  • #62
woodyzzz said:
Is it correct to assume that the current value is the same throughout the circuit ? or would you obtain different value i.e. across the resistor
It is a series circuit, so there's no option: The current must be identical throughout.
 

Similar threads

AC Cirucits - Impedance Values
  • · Replies 5 ·
Replies
5
Views
2K
Engineering AC Circuit Power/impedance question
  • · Replies 16 ·
Replies
16
Views
3K
Engineering Calculating Power Factor in an AC circuit, given voltage and current
  • · Replies 5 ·
Replies
5
Views
2K
Engineering Intro to Power Systems: Calculating Power
  • · Replies 7 ·
Replies
7
Views
2K
Engineering Calculating Power Losses in an AC Induction Motor
  • · Replies 7 ·
Replies
7
Views
3K
Engineering Calculating Power Lost in a Resistor (within Transformer Circuit)
  • · Replies 4 ·
Replies
4
Views
2K
AC Power and Effective Currents
  • · Replies 8 ·
Replies
8
Views
4K
What Is the Apparent Power in a Circuit with a Power Factor of 0.72?
  • · Replies 1 ·
Replies
1
Views
5K
Engineering Calculating Voltage Source in AC Circuit
  • · Replies 2 ·
Replies
2
Views
2K
Engineering How am I susposed to find the active power here?
  • · Replies 9 ·
Replies
9
Views
2K