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Power in Circuits Calculator

Calculate Electrical Power & Energy

System Properties

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Enter values above to calculate power or energy in circuits

About Power in Circuits

Electrical power is the rate at which energy is transferred or converted in a circuit. It is a key concept in both DC and AC circuits, with different formulas for true, apparent, and reactive power.

Key Formulas:

  • P = VI - Power from voltage and current
  • P = I²R - Power from current and resistance
  • P = V²/R - Power from voltage and resistance
  • P = √3VIcosφ - Three-phase AC true power
  • S = VI - Apparent power (AC)
  • Q = VI sinφ - Reactive power (AC)
  • E = Pt - Energy from power and time

Power Types:

  • True (Real) Power (P): Actual power consumed (W)
  • Apparent Power (S): Product of RMS voltage and current (VA)
  • Reactive Power (Q): Power stored and released (VAR)

Units:

  • Power: W, kW, MW
  • Voltage: V
  • Current: A
  • Resistance: Ω
  • Energy: J, Wh, kWh
  • Time: s, min, h

Applications:

  • Electrical circuit analysis
  • Power system design
  • Energy consumption and billing
  • Motor and transformer sizing
  • Renewable energy systems

AC vs DC:

  • DC: Power = VI, I²R, or V²/R
  • AC Single Phase: True Power = VIcosφ, Apparent = VI, Reactive = VIsinφ
  • AC Three Phase: True Power = √3VIcosφ, Apparent = √3VI, Reactive = √3VIsinφ