1. What is the Power Equation?

The power equation (P = V × I × PF) calculates real power in watts in an AC circuit from voltage, current, and power factor. It accounts for both the magnitude of current/voltage and their phase relationship.

2. How Does the Calculator Work?

The calculator uses the power equation:

Where:

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

Explanation: The equation shows that real power depends not just on voltage and current, but also on how in-phase they are (power factor).

3. Importance of Power Calculation

Details: Accurate power calculation is essential for electrical system design, energy consumption estimation, and proper sizing of electrical components.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, and power factor (0 to 1). For purely resistive loads, power factor is 1. 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 to useful work (range 0-1).

Q2: What's the difference between watts and VA?
A: Watts measure real power, while VA (volt-amps) measure apparent power (V × I). The ratio between them is the power factor.

Q3: When is power factor not 1?
A: Power factor is less than 1 in circuits with inductive or capacitive loads (motors, transformers, fluorescent lighting).

Q4: How does this differ from DC power calculation?
A: In DC circuits, power is simply V × I since there's no phase difference (PF = 1 always).

Q5: Why is power factor important?
A: Low power factor means more current is needed for the same real power, increasing energy losses in distribution systems.