1. What is the Watts Formula?

The Watts formula (P = V × I × PF) calculates real power in an electrical circuit. It accounts for voltage (V), current (I), and the power factor (PF) which represents the phase difference between voltage and current 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 is less than 1.

3. Importance of Power Calculation

Details: Calculating real power is essential for determining energy consumption, sizing electrical components, and ensuring electrical system efficiency.

4. Using the Calculator

Tips: Enter voltage in volts, current in amperes, and power factor (1 for DC or resistive AC 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 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 is power factor not 1?
A: In AC circuits with inductive or capacitive loads (motors, transformers, etc.) where current and voltage are out of phase.

Q3: How do I measure power factor?
A: Power factor can be measured with a power meter or calculated as the cosine of the phase angle between voltage and current.

Q4: What's 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 power supplies often have PF=0.6-0.7.

Q5: Why is low power factor a problem?
A: Low PF causes higher current for the same real power, increasing energy losses in wiring and requiring larger capacity equipment.