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Electrical Power Formula:
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Electrical power (measured in watts) represents the rate at which electrical energy is transferred by an electric circuit. The basic formula for power in DC circuits or AC circuits with purely resistive loads is P = V × I. For AC circuits with reactive components, we must include the power factor (PF).
The calculator uses the electrical power formula:
Where:
Explanation: This formula calculates real power in an AC circuit, accounting for the phase difference between voltage and current through the power factor.
Details: Accurate power calculation is essential for designing electrical systems, sizing components, calculating energy consumption, and determining electrical costs.
Tips: Enter voltage in volts, current in amperes, and power factor (1 for DC or resistive AC circuits, less than 1 for reactive AC circuits). All values must be valid (voltage > 0, current > 0, 0 ≤ PF ≤ 1).
Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing how effectively current is being converted into useful work (range: 0 to 1).
Q2: When should I use PF = 1?
A: For DC circuits or purely resistive AC loads (like incandescent lights or heaters), use PF = 1. For motors, transformers, or fluorescent lights, PF is typically less than 1.
Q3: What's the difference between watts and volt-amps?
A: Watts measure real power, while volt-amps (VA) measure apparent power. The ratio between them is the power factor (Watts = VA × PF).
Q4: How does this relate to energy consumption?
A: Energy (kWh) = Power (kW) × Time (hours). This calculator gives you the power component of that equation.
Q5: Can I use this for three-phase power?
A: For balanced three-phase systems, multiply by √3 (about 1.732). The formula becomes P = √3 × V × I × PF.