1. What is the Power Formula?

The power formula P = V²/R calculates the electrical power dissipated by a resistor when voltage and resistance are known. This is derived from Ohm's law and the basic power equation.

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 formula shows that power is proportional to the square of the voltage and inversely proportional to the resistance.

3. Importance of Power Calculation

Details: Calculating power dissipation is crucial for selecting appropriate resistors, preventing overheating, and ensuring circuit reliability and safety.

4. Using the Calculator

Tips: Enter voltage in volts 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 voltage squared?
A: Because power equals voltage times current (P = V×I), and according to Ohm's law, current is proportional to voltage (I = V/R), so P = V×(V/R) = V²/R.

Q2: What happens if resistance is zero?
A: Division by zero is undefined. In practical circuits, extremely low resistance can cause excessive current flow and potential damage.

Q3: How does this relate to resistor power ratings?
A: Resistors have maximum power ratings. The calculated power should not exceed the resistor's rated power to prevent overheating and failure.

Q4: Can this formula be used for AC circuits?
A: For AC circuits with resistive loads, the formula applies using RMS voltage values. For reactive loads, additional factors must be considered.

Q5: What are typical power values in electronic circuits?
A: Power values range from milliwatts (mW) in small signal circuits to watts (W) in power applications, with resistors typically rated from 0.125W to several watts.