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Power Formulas:
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Resistor power calculation determines the amount of power dissipated by a resistor in an electrical circuit. This is crucial for selecting resistors with appropriate power ratings to prevent overheating and failure.
The calculator uses two fundamental power formulas:
Where:
Explanation: Both formulas are derived from Ohm's Law (V = IR) and the fundamental power equation. They provide two different ways to calculate the same physical quantity.
Details: Accurate power calculation is essential for circuit design, component selection, and ensuring electrical safety. Resistors must be rated for the power they will dissipate to avoid damage.
Tips: Enter current in amperes, voltage in volts, and resistance in ohms. All values must be positive numbers. The calculator will compute power using both formulas.
Q1: Which formula should I use?
A: Use P = I²R when you know current and resistance. Use P = VI when you know voltage and current. Both give the same result when all values are consistent with Ohm's Law.
Q2: What happens if the calculated power exceeds the resistor rating?
A: The resistor may overheat, potentially causing failure, fire hazard, or circuit malfunction. Always use resistors with adequate power ratings.
Q3: Are there other power formulas?
A: Yes, P = V²/R is another common formula derived from the same principles, useful when you know voltage and resistance.
Q4: How does temperature affect power dissipation?
A: Resistor power ratings typically assume specific ambient temperatures. Higher temperatures may require derating (using a lower maximum power).
Q5: Can I use this for AC circuits?
A: For AC circuits with resistive loads, these formulas work with RMS values. For reactive loads, additional considerations are needed.