Power Dissipated By Resistor Calculator

Power Dissipation Formulas:

\[ P = \frac{V^2}{R} \quad \text{or} \quad P = I^2 R \]

Power Dissipated (P):

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1. What is Power Dissipation in Resistors?

Power dissipation in resistors refers to the electrical power converted to heat when current flows through a resistor. This is calculated using Ohm's law and power formulas to determine how much energy the resistor dissipates as heat.

2. How Does the Calculator Work?

The calculator uses the power dissipation formulas:

\[ P = \frac{V^2}{R} \quad \text{or} \quad P = I^2 R \]

Where:

\( P \) — Power dissipated (Watts)
\( V \) — Voltage across resistor (Volts)
\( I \) — Current through resistor (Amperes)
\( R \) — Resistance (Ohms)

Explanation: The calculator automatically selects the appropriate formula based on the input values provided. You can enter any two of the three variables (V, I, R) to calculate power.

3. Importance of Power Calculation

Details: Calculating power dissipation is crucial for selecting proper resistor wattage ratings, preventing overheating, ensuring circuit reliability, and designing efficient electronic systems.

4. Using the Calculator

Tips: Enter any two known values (voltage and resistance, or current and resistance, or voltage and current). All values must be positive numbers. The calculator will compute the power dissipation in watts.

5. Frequently Asked Questions (FAQ)

Q1: What happens if power dissipation exceeds resistor rating?
A: The resistor will overheat, potentially causing failure, fire hazard, or circuit malfunction. Always use resistors with adequate power ratings.

Q2: Can I use both formulas interchangeably?
A: Yes, both formulas are mathematically equivalent when derived from Ohm's law (V = IR). Choose based on which variables you know.

Q3: What are common resistor power ratings?
A: Common ratings include 1/8W, 1/4W, 1/2W, 1W, 2W, 5W, and higher for power applications.

Q4: How does temperature affect power dissipation?
A: Higher temperatures reduce a resistor's maximum power rating. Derating is often necessary in high-temperature environments.

Q5: When should I use P = V²/R vs P = I²R?
A: Use P = V²/R when you know voltage and resistance; use P = I²R when you know current and resistance; use P = VI when you know both voltage and current.