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 the actual power consumed 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 or AC circuits with purely resistive loads, the power factor is 1. For AC circuits with reactive components, the power factor accounts for phase difference between voltage and current.

3. Understanding Power Factor

Details: Power factor represents the ratio of real power to apparent power. A PF of 1 means all power is real (useful) power. Lower PF indicates more reactive power in the system.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, 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 (watts) does actual work, while apparent power (VA) is the product of voltage and current. The ratio is the power factor.

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

Q3: What's a typical power factor for household appliances?
A: Resistive loads (heaters, incandescent lights) have PF≈1. Motors typically have PF=0.8-0.9. Electronics with switching power supplies may have PF=0.6-0.7.

Q4: How does power factor affect electrical bills?
A: Some utilities charge industrial customers for low power factor since it increases current flow without delivering more useful power.

Q5: Can power factor be greater than 1?
A: Normally no. Values >1 usually indicate measurement errors or very unusual waveform distortion.