1. What is the Power Equation for Resistors?

The power equation P = V²/R calculates the power dissipated by a resistor in an electrical circuit, where P is power in watts, V is voltage across the resistor in volts, and R is resistance in ohms.

2. How Does the Calculator Work?

The calculator uses the power equation:

Where:

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

Explanation: This equation calculates the power dissipated as heat by a resistor when a specific voltage is applied across it.

3. Importance of Power Rating Calculation

Details: Calculating power dissipation is crucial for selecting resistors with appropriate power ratings to prevent overheating and ensure circuit reliability.

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 rating important for resistors?
A: Resistors must be rated for the power they will dissipate to prevent overheating, damage, or circuit failure.

Q2: What happens if a resistor exceeds its power rating?
A: The resistor may overheat, change value, or fail completely, potentially damaging the circuit.

Q3: Are there other power equations for resistors?
A: Yes, P = I²×R and P = V×I can also be used, depending on which parameters are known.

Q4: How do I select the right resistor power rating?
A: Choose a resistor with a power rating at least 1.5-2 times the calculated power dissipation for safety margin.

Q5: Does this equation work for AC circuits?
A: For AC circuits with resistive loads, use RMS voltage values in the calculation.