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Power Equation:
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Power calculation using the formula W = V × A is fundamental in electrical engineering and physics. It calculates electrical power in watts for DC circuits or resistive AC circuits, representing the rate at which electrical energy is transferred by an electric circuit.
The calculator uses the power equation:
Where:
Explanation: This formula represents the basic relationship between voltage, current, and power in electrical systems. One watt equals one joule per second, representing the rate of energy conversion or transfer.
Details: Accurate power calculation is essential for circuit design, electrical safety, energy consumption analysis, equipment sizing, and determining electrical load capacity in residential, commercial, and industrial applications.
Tips: Enter voltage in volts and current in amperes. Both values must be positive numbers. The calculator will compute the power in watts instantly.
Q1: Can this formula be used for AC circuits?
A: This simple formula works for DC circuits and resistive AC circuits. For reactive AC circuits, power factor must be considered using P = V × I × PF.
Q2: What is the difference between watts and volt-amperes?
A: Watts represent real power, while volt-amperes represent apparent power. In DC or purely resistive AC circuits, they are equal. In reactive circuits, watts are less than volt-amperes.
Q3: How does this relate to energy consumption?
A: Power (watts) multiplied by time (hours) gives energy consumption in watt-hours. For example, a 100W device running for 10 hours consumes 1,000 watt-hours (1 kWh).
Q4: What are typical power ratings for household appliances?
A: LED bulb: 5-15W, Laptop: 50-100W, Refrigerator: 100-400W, Microwave: 800-1500W, Electric heater: 1500-3000W.
Q5: How do I calculate current from power and voltage?
A: Use I = P ÷ V. For example, a 1200W device at 120V draws 10A of current (1200 ÷ 120 = 10).