1. What is a Power Resistor Calculator?

Definition: This calculator determines the power dissipation in a resistor based on the voltage across it and its resistance.

Purpose: It helps electronics engineers and hobbyists select resistors with appropriate power ratings for their circuits.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P \) — Power dissipation (watts)
• \( V \) — Voltage across resistor (volts)
• \( R \) — Resistance (ohms)

Explanation: The voltage squared divided by resistance gives the power dissipated as heat in the resistor.

3. Importance of Power Calculation

Details: Proper power calculation ensures resistors won't overheat and fail, maintaining circuit reliability and safety.

4. Using the Calculator

Tips: Enter the voltage across the resistor and its resistance. Resistance must be > 0 ohms.

5. Frequently Asked Questions (FAQ)

Q1: Why is power calculation important for resistors?
A: Resistors must be rated for at least the calculated power to prevent overheating and failure.

Q2: What if my resistor gets too hot?
A: Choose a resistor with higher power rating or use multiple resistors in series/parallel.

Q3: Does this work for AC circuits?
A: For AC, use RMS voltage values in the calculation.

Q4: What's a typical resistor power rating?
A: Common ratings are 1/4W, 1/2W, 1W, 5W, etc. Always choose higher than calculated.

Q5: How does resistance affect power?
A: Lower resistance with same voltage means higher power dissipation.