1. What is the Power Formula?

The power formula P = I² × R calculates electrical power dissipated in a resistor, where P is power in watts, I is current in amperes, and R is resistance in ohms. This is derived from Joule's law of heating.

2. How Does the Calculator Work?

The calculator uses the power formula:

Where:

• \( P \) — Power (watts)
• \( I \) — Current (amperes)
• \( R \) — Resistance (ohms)

Explanation: The formula shows that power is proportional to the square of the current and directly proportional to the resistance in the circuit.

3. Importance of Power Calculation

Details: Calculating power dissipation is crucial for circuit design, component selection, thermal management, and ensuring electrical safety in various applications.

4. Using the Calculator

Tips: Enter current in amperes and resistance in ohms. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why is power proportional to current squared?
A: Because both voltage (V = I × R) and current contribute to power (P = V × I), resulting in P = I² × R when substituting.

Q2: What are typical power values in circuits?
A: Power values vary widely from milliwatts in small electronics to kilowatts in power systems, depending on current and resistance values.

Q3: When should I use this formula?
A: Use this formula when you know both current and resistance values and need to calculate power dissipation in resistive components.

Q4: Are there limitations to this formula?
A: This formula applies specifically to resistive loads. For reactive components (inductors, capacitors), additional factors like power factor must be considered.

Q5: How does temperature affect the calculation?
A: Resistance often changes with temperature, which may affect power calculations in real-world applications where temperature varies significantly.