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