1. What is the Power Formula?

The power formula (P = V × I × PF) calculates the real power in an AC circuit, measured in watts. It accounts for voltage, current, and the power factor which represents the phase difference between voltage and current.

2. How Does the Calculator Work?

The calculator uses the power formula:

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 or AC circuits with purely resistive loads, the power factor is 1. For AC circuits with reactive components, the power factor is less than 1.

3. Importance of Power Calculation

Details: Accurate power calculation is essential for electrical system design, energy consumption estimation, circuit protection sizing, and energy efficiency analysis.

4. Using the Calculator

Tips: Enter voltage in volts, current in amperes, and power factor (default is 1 for DC or resistive AC circuits). 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, representing how effectively current is being converted into useful work.

Q2: When should I use power factor less than 1?
A: For AC circuits with inductive or capacitive loads (motors, transformers, fluorescent lighting) where current and voltage are out of phase.

Q3: What's the difference between real, apparent, and reactive power?
A: Real power (W) does actual work, apparent power (VA) is voltage × current, and reactive power (VAR) is the non-working power in reactive components.

Q4: How can I improve power factor?
A: Adding capacitors (for inductive loads) or inductors (for capacitive loads) can bring voltage and current back in phase.

Q5: Does this formula work for three-phase power?
A: For balanced three-phase systems, multiply by √3 (P = √3 × V × I × PF). Use line-to-line voltage and line current.