1. What is the Power Formula?

The power formula \( P = \frac{V^2}{R} \) calculates the electrical power dissipated in a resistive component when the voltage across it and its resistance are known. This is derived from combining Ohm's Law with the basic power formula.

2. How Does the Calculator Work?

The calculator uses the power formula:

Where:

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

Explanation: The power dissipated in a resistor increases with the square of the voltage across it and decreases with increasing resistance.

3. Importance of Power Calculation

Details: Calculating power is essential for designing electrical circuits, selecting appropriate components, and ensuring safe operation within power ratings.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What are other forms of the power formula?
A: Power can also be calculated as \( P = V \times I \) or \( P = I^2 \times R \) where I is current.

Q2: What are typical power ratings for resistors?
A: Common resistor power ratings include 1/8W, 1/4W, 1/2W, 1W, and higher for power applications.

Q3: Does this formula work for AC circuits?
A: For AC, use RMS voltage values and consider that reactance may replace resistance in reactive components.

Q4: What happens if power exceeds a component's rating?
A: Components may overheat, fail, or in extreme cases, cause fires. Always design with safety margins.

Q5: How does temperature affect power calculations?
A: Resistance often changes with temperature, which affects power dissipation in real-world applications.