1. What is a Watt?

The watt (W) is the SI unit of power, equivalent to one joule per second. It measures the rate of energy conversion or transfer. In electrical terms, power in watts is the product of voltage (V), current (I), and power factor (PF).

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. Importance of Power Calculation

Details: Calculating power is essential for designing electrical systems, determining energy consumption, sizing components, and ensuring electrical safety.

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 watts and volt-amps?
A: Watts measure real power, while volt-amps (VA) measure apparent power. They're equal when power factor is 1.

Q2: Why is power factor important?
A: Power factor indicates efficiency of power usage. Low PF means more current is needed for the same real power.

Q3: What's a typical power factor value?
A: For resistive loads (heaters, incandescent lights) it's 1. For motors it's typically 0.8-0.9, and for electronic devices 0.6-0.7.

Q4: How does this relate to energy consumption?
A: Energy (kWh) = Power (kW) × Time (hours). Watts measure instantaneous power.

Q5: Can I use this for three-phase systems?
A: For balanced three-phase systems, multiply by √3 (about 1.732) for line-to-line voltage.