1. What is the Power Equation?

The power equation (P = V × I × PF) calculates the real power in watts consumed by an electrical device. It accounts for voltage, current, and power factor (which represents phase difference between voltage and current in AC circuits).

2. How Does the Calculator Work?

The calculator uses the power equation:

Where:

• \( P \) — Power in watts (W)
• \( V \) — Voltage in volts (V)
• \( I \) — Current in amperes (A)
• \( PF \) — Power factor (unitless, 0 to 1)

Explanation: For DC circuits, power factor is 1. For AC circuits, power factor accounts for phase difference between voltage and current.

3. Importance of Power Calculation

Details: Calculating power consumption is essential for electrical system design, energy efficiency assessments, circuit protection sizing, and estimating operating costs.

4. Using the Calculator

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, 0 ≤ PF ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, ranging from 0 to 1. It represents how effectively current is being converted into useful work.

Q2: When should I use power factor = 1?
A: Use PF=1 for DC circuits or purely resistive AC loads (like incandescent lights or heaters). For inductive loads (motors, transformers), PF is typically 0.8-0.95.

Q3: How do I measure current and voltage?
A: Use a multimeter - measure voltage across the device and current in series with the device. For AC, use true-RMS meters for accurate measurements.

Q4: What's the difference between real power and apparent power?
A: Real power (watts) does actual work, while apparent power (VA) is the product of V×I without power factor consideration.

Q5: Can I use this for three-phase systems?
A: For balanced three-phase systems, multiply by √3 (use P = √3 × V × I × PF). This calculator is for single-phase systems.