1. What is the Watts Calculation Formula?

The Watts Calculation Formula (P = V × I × PF) calculates real power in an AC or DC electrical circuit. It accounts for voltage, current, and in AC circuits, 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, power factor is 1. For AC circuits, power factor accounts for the phase difference between voltage and current waveforms.

3. Importance of Power Calculation

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

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between real, apparent, and reactive power?
A: Real power (P, in watts) does actual work. Apparent power (S, in VA) is V×I. Reactive power (Q, in VAR) is power that oscillates between source and load.

Q2: When is power factor not 1?
A: In AC circuits with inductive or capacitive loads (motors, transformers, etc.) where current and voltage waveforms are out of phase.

Q3: How can I improve power factor?
A: By adding capacitors (for inductive loads) or inductors (for capacitive loads) to bring voltage and current back in phase.

Q4: What's typical power factor for household appliances?
A: Resistive loads (heaters, incandescent lights) have PF=1. Motors typically 0.7-0.9. Electronics with power supplies often 0.6-0.8.

Q5: Why does power factor matter?
A: Low PF increases current for same real power, causing higher energy losses in wiring and requiring larger equipment.