Home
Back
Power Dissipation Formula:
| From: | To: |
Resistance power dissipation refers to the power converted to heat when electric current flows through a resistor. It's calculated using Joule's first law: P = I²R, where P is power in watts, I is current in amperes, and R is resistance in ohms.
The calculator uses the power dissipation formula:
Where:
Explanation: The formula shows that power dissipation increases with the square of the current and linearly with resistance. This means small increases in current can lead to significant increases in power dissipation.
Details: Calculating power dissipation is crucial for selecting appropriate resistor wattage ratings, preventing overheating, ensuring circuit reliability, and designing efficient electronic systems. Exceeding a resistor's power rating can lead to failure or fire hazard.
Tips: Enter current in amperes and resistance in ohms. Both values must be positive numbers. The calculator will compute the power dissipation in watts.
Q1: Why is power dissipation important in circuit design?
A: Proper power dissipation calculation ensures components operate within their thermal limits, preventing damage and ensuring circuit longevity and safety.
Q2: What happens if power dissipation exceeds a resistor's rating?
A: The resistor may overheat, change value, fail catastrophically, or in extreme cases, cause a fire. Always use resistors with appropriate wattage ratings.
Q3: Can this formula be used for AC circuits?
A: For purely resistive AC circuits, the formula works with RMS current values. For reactive components, additional considerations are needed.
Q4: How does temperature affect power dissipation?
A: As resistors heat up, their resistance may change, which can affect power dissipation. Some resistors have derating curves for high-temperature operation.
Q5: Are there other formulas for power calculation?
A: Yes, power can also be calculated as P = V²/R or P = VI, where V is voltage across the resistor. All three formulas are equivalent for resistive loads.