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Power Formula:
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Electrical power is the rate at which electrical energy is transferred by an electric circuit. It is measured in watts (W) and represents the amount of work done or energy consumed per unit time in electrical systems.
The calculator uses the power formula:
Where:
Explanation: For DC circuits, power factor is 1. For AC circuits, power factor accounts for the phase difference between voltage and current, representing the efficiency of power usage.
Details: Accurate power calculation is essential for electrical system design, energy consumption analysis, circuit protection sizing, and determining the capacity requirements for electrical components and systems.
Tips: Enter voltage in volts, current in amperes, and power factor (use 1.0 for DC circuits). All values must be valid (voltage > 0, current > 0, power factor between 0-1).
Q1: What is the difference between real power and apparent power?
A: Real power (P) is the actual power consumed and measured in watts. Apparent power (S) is the product of voltage and current, measured in volt-amperes (VA). Power factor = Real Power / Apparent Power.
Q2: When should I use power factor less than 1?
A: Use power factor less than 1 for AC circuits with inductive or capacitive loads (motors, transformers, fluorescent lighting) where current and voltage are out of phase.
Q3: What are typical power factor values?
A: Residential: 0.85-0.95, Industrial: 0.75-0.90, Commercial: 0.80-0.95. DC circuits always have power factor of 1.
Q4: How does power calculation affect electrical bills?
A: For residential users, power consumption in watts determines energy usage (kWh). For industrial users, low power factor may result in penalties from utility companies.
Q5: Can this calculator be used for three-phase systems?
A: For three-phase systems, use the formula: P = √3 × V × I × PF, where V is line-to-line voltage and I is line current.