1. What is the Power Equation?

The power equation \( P = \frac{V^2}{R} \) calculates the power dissipated through a resistor when the voltage across it and its resistance are known. This is derived from Joule's first law and is fundamental in electrical engineering.

2. How Does the Calculator Work?

The calculator uses the power equation:

Where:

• \( P \) — Power in watts (W)
• \( V \) — Voltage in volts (V)
• \( R \) — Resistance in ohms (Ω)

Explanation: The power dissipated in a resistor is proportional to the square of the voltage across it and inversely proportional to its resistance.

3. Importance of Power Calculation

Details: Calculating power dissipation is crucial for designing circuits, selecting appropriate resistor wattage ratings, and preventing component failure due to overheating.

4. Using the Calculator

Tips: Enter voltage in volts and resistance in ohms. Both values must be positive (resistance must be greater than zero).

5. Frequently Asked Questions (FAQ)

Q1: What happens if the power exceeds a resistor's rating?
A: The resistor may overheat, potentially causing failure, fire hazard, or circuit malfunction.

Q2: Can this equation be used for AC circuits?
A: Yes, but with RMS voltage values for AC circuits.

Q3: How does this relate to Ohm's Law?
A: This is derived from combining Ohm's Law (V=IR) with the power definition (P=VI).

Q4: What are typical resistor power ratings?
A: Common ratings include 1/8W, 1/4W, 1/2W, 1W, with higher ratings available for power applications.

Q5: How does temperature affect the calculation?
A: Resistance may change with temperature, affecting actual power dissipation in real-world conditions.