1. What is the Power Formula?

The power formula (P = V × I × PF) calculates real power in an AC circuit, accounting 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:

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

Explanation: The formula calculates the actual power being used in a circuit, as opposed to the apparent power (V × I). The power factor accounts for phase differences in AC circuits.

3. Importance of Power Calculation

Details: Accurate power calculation is essential for electrical system design, energy efficiency assessments, circuit protection, and proper equipment sizing.

4. Using the Calculator

Tips: Enter voltage in volts, current in amperes, and power factor (between 0 and 1). For DC circuits or purely resistive AC loads, use PF = 1.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between real power and apparent power?
A: Real power (P) is the actual power consumed, while apparent power (S = V × I) is the product of voltage and current. The ratio P/S is the power factor.

Q2: What are typical power factor values?
A: For residential loads, PF is typically 0.8-0.95. Industrial motors might have PF of 0.7-0.9. Pure resistive loads (heaters, incandescent lights) have PF = 1.

Q3: Why does power factor matter?
A: Low power factor means more current is needed for the same real power, increasing energy losses in distribution systems. Utilities often charge penalties for low PF.

Q4: How can power factor be improved?
A: Power factor correction capacitors can be added to counteract inductive loads (motors, transformers) which cause lagging power factors.

Q5: Is power factor relevant for DC circuits?
A: No, in DC circuits power is simply V × I as there's no phase difference between voltage and current.