1. What is the Power Formula?

The power formula (P = V × I × PF) calculates real power in watts from voltage, current, and power factor. It's fundamental in electrical engineering for determining power consumption in AC circuits.

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

3. Importance of Power Calculation

Details: Accurate power calculation is essential for circuit design, electrical safety, energy efficiency assessment, and proper sizing of electrical components.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, and power factor (1 for DC circuits, 0 to 1 for AC circuits). All values must be valid (voltage > 0, current > 0, 0 ≤ PF ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What if I don't know the power factor?
A: For DC circuits, use 1. For AC resistive loads (like heaters), use 1. For motors or inductive loads, typical values range from 0.8 to 0.95.

Q2: How does this differ from VA (volt-amps)?
A: VA represents apparent power (V × I), while watts represent real power (V × I × PF). They're equal only when PF = 1.

Q3: Why is power factor important?
A: Low power factor means more current is needed to deliver the same real power, increasing energy losses in distribution systems.

Q4: Can I use this for three-phase systems?
A: For balanced three-phase systems, multiply by √3 (≈1.732). The formula becomes P = √3 × V × I × PF.

Q5: What's typical household voltage?
A: In North America, 120V for most outlets and 240V for large appliances. In Europe/Asia, typically 220-240V.