1. What is the Power Formula?

The power formula (P = V × I × PF) calculates electrical power in watts from voltage, current, and power factor. It's fundamental in electrical engineering for determining power consumption in AC and DC 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, power factor is 1. For AC circuits, power factor accounts for phase difference between voltage and current.

3. Importance of Power Calculation

Details: Accurate power calculation is essential for circuit design, energy consumption estimation, electrical safety, and proper sizing of electrical components.

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, power factor between 0-1).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between real power and apparent power?
A: Real power (P) is actual consumed power in watts. Apparent power (S = V × I) is in volt-amperes (VA). The ratio P/S 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 waveforms are out of phase.

Q3: How do I measure these values?
A: Use a multimeter for voltage and current. Power factor meters or specialized equipment are needed for PF measurement.

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

Q5: Why does power factor matter?
A: Low power factor means higher current is needed for same real power, increasing energy losses in distribution systems.