1. What is the Power Formula?

The power formula P = I² × R calculates electrical power in watts, where I is current in amperes and R is resistance in ohms. This is derived from combining Ohm's law (V = I × R) and the power formula (P = V × I).

2. How Does the Calculator Work?

The calculator uses the power formula:

Where:

• \( P \) — Power in watts (W)
• \( I \) — Current in amperes (A)
• \( R \) — Resistance in ohms (Ω)

Explanation: This formula calculates the power dissipated as heat in a resistive component when a specific current flows through it.

3. Importance of Power Calculation

Details: Calculating power dissipation is crucial for designing electrical circuits, selecting appropriate components, preventing overheating, and ensuring system safety and efficiency.

4. Using the Calculator

Tips: Enter current in amperes and resistance in ohms. Both values must be positive numbers. The calculator will compute the power in watts.

5. Frequently Asked Questions (FAQ)

Q1: What are the other power formulas?
A: Power can also be calculated as P = V × I (voltage times current) or P = V²/R (voltage squared divided by resistance).

Q2: When is this formula most applicable?
A: This formula is particularly useful when you know the current and resistance but not the voltage in a DC circuit.

Q3: Does this work for AC circuits?
A: For AC circuits with resistive loads only, this formula works with RMS values. For reactive loads, additional factors must be considered.

Q4: What is a typical power rating for resistors?
A: Common resistor power ratings include 0.125W, 0.25W, 0.5W, 1W, 2W, and higher for specialized applications.

Q5: What happens if power exceeds a component's rating?
A: Components will overheat, potentially causing failure, fire hazard, or damage to other circuit elements.