1. What is the Power Equation?

The power equation (P = I²R) calculates the power dissipated by a resistor in an electrical circuit. It shows the relationship between current (I), resistance (R), and power (P).

2. How Does the Calculator Work?

The calculator uses the power equation:

Where:

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

Explanation: The power dissipated by a resistor increases with the square of the current flowing through it and directly with its resistance.

3. Importance of Power Calculation

Details: Calculating power dissipation is crucial for selecting resistors with appropriate wattage ratings to prevent overheating and failure.

4. Using the Calculator

Tips: Enter current in amperes and resistance in ohms. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is power proportional to current squared?
A: Because both the voltage across the resistor and the current through it increase with current (V=IR), making power (P=VI) proportional to I².

Q2: What happens if power exceeds resistor rating?
A: The resistor may overheat, potentially causing failure, fire hazard, or circuit malfunction.

Q3: How do I choose a resistor wattage?
A: Select a resistor with a wattage rating at least twice the calculated power for safety margin.

Q4: Does this equation work for AC circuits?
A: Yes, when using RMS current values for AC circuits with resistive loads.

Q5: What about parallel or series resistors?
A: Calculate power for each resistor individually based on the current through it or voltage across it.