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Wattage Formula:
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Wattage (power) is the rate at which electrical energy is transferred by an electric circuit. It represents how much work can be done with the electric current and is measured in watts (W).
The calculator uses the wattage formula:
Where:
Explanation: For DC circuits or AC circuits with purely resistive loads, the power factor is 1. For AC circuits with reactive components, the power factor accounts for the phase difference between voltage and current.
Details: Power factor is crucial in AC circuits as it represents the efficiency with which current is being converted into useful work. A low power factor (below 0.9) indicates poor electrical efficiency and may result in higher utility charges for industrial customers.
Tips: Enter voltage in volts, current in amperes, and power factor (1 for DC circuits or resistive AC loads). All values must be valid (voltage > 0, current > 0, power factor between 0-1).
Q1: What's the difference between real power and apparent power?
A: Real power (watts) is the actual power consumed, while apparent power (VA) is the product of voltage and current. The ratio is the power factor.
Q2: When should I use a power factor less than 1?
A: For AC circuits with inductive or capacitive loads (motors, transformers, fluorescent lighting), use the appropriate power factor (typically 0.8-0.95 for motors).
Q3: What's a typical power factor for household appliances?
A: Resistive loads (heaters, incandescent lights) have PF=1. Motors typically 0.8-0.9. Electronics with switching power supplies often 0.6-0.7.
Q4: How does power factor affect energy bills?
A: Residential customers usually pay for real power (watts). Industrial customers may be charged for low power factor as it increases current in distribution systems.
Q5: Can power factor be greater than 1?
A: Normally no. Values above 1 usually indicate measurement errors or special cases with non-sinusoidal waveforms.