Resistor Power Rating: What Does It Mean?

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SUMMARY

The discussion clarifies the significance of power ratings on resistors, emphasizing that resistors are not only defined by their resistance values (e.g., 20 ohm, 40 ohm, 2 Megaohm) but also by their power dissipation capabilities. The power rating indicates the maximum power a resistor can handle without overheating, which is critical for preventing damage in circuits. The formulas P = V^2/R and P = I^2 * R are referenced to explain how voltage and current relate to power dissipation in resistors.

PREREQUISITES
  • Understanding of Ohm's Law and basic electrical principles
  • Familiarity with resistor types and their applications
  • Knowledge of power dissipation in electrical components
  • Basic circuit analysis skills
NEXT STEPS
  • Research resistor power ratings and their implications in circuit design
  • Learn about different types of resistors and their thermal characteristics
  • Explore the relationship between voltage, current, and power in electrical circuits
  • Study practical applications of resistors in limiting current and protecting components
USEFUL FOR

Electronics enthusiasts, electrical engineers, and anyone involved in circuit design and analysis will benefit from this discussion, particularly those interested in understanding resistor specifications and their impact on circuit performance.

quantum13
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i have a question about resistors. i thought they were described by their resistance - 20 ohm, 40 ohm, 2 Megaohm, etc.

how come I see "power" values on resistors? for example my lightbulb says 40 watts. but i thought the power is simply P = V^2/R and that would depend the voltage of my power outlet whatever that happens to be. The power would only be partially determined by the lightbulb. so what does it mean to see a power value on a resistor?
 
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Q, If you put too much current through your resistor it will get too hot. There are different resistor types intended for different degrees of power they need to dissipate. Maybe P=I^2 * R, so it's a current limiting rating.
 

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