1. What is Power Dissipation in a Resistor?

Power dissipation in a resistor refers to the process where electrical energy is converted to heat energy as current flows through a resistance. This is described by Joule's first law, which states that the power generated by a resistor is proportional to the square of the current flowing through it and its resistance.

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: The power dissipated by a resistor increases with the square of the current flowing through it, making current the dominant factor in power dissipation calculations.

3. Importance of Power Calculation

Details: Calculating power dissipation is crucial for selecting appropriate resistor wattage ratings, preventing overheating, ensuring circuit reliability, and maintaining safety standards in electronic designs.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why does power increase with the square of current?
A: Because both voltage drop across the resistor (V = I×R) and current contribute to power (P = V×I), resulting in P = I²×R.

Q2: What happens if a resistor dissipates too much power?
A: The resistor will overheat, potentially causing failure, circuit damage, or in extreme cases, becoming a fire hazard.

Q3: How do I select the right resistor wattage?
A: Choose a resistor with a wattage rating at least 1.5-2 times the calculated power dissipation to provide a safety margin.

Q4: Can this formula be used for AC circuits?
A: Yes, for resistive loads in AC circuits, you can use RMS values for current to calculate power dissipation.

Q5: What are other power formulas for resistors?
A: P = V²/R and P = V×I are equivalent formulas that can be used depending on what values are known.