Understanding High Power Resistor Ratings: A Beginner's Guide

Click For Summary
SUMMARY

This discussion clarifies the nomenclature of high power resistors, specifically the notation "3R9ohm" and "4R7ohm," which represent resistive values of 3.9 Ohms and 4.7 Ohms, respectively. It emphasizes the distinction between resistance and power ratings, which can range from approximately 1/8 Watt to several hundred Watts. The conversation highlights the importance of understanding the purpose of the resistor in relation to its power rating, as higher power resistors are typically larger due to their heat dissipation requirements.

PREREQUISITES
  • Understanding of Ohm's Law (V=IR)
  • Familiarity with resistor nomenclature
  • Knowledge of power ratings in electronic components
  • Basic concepts of heat dissipation in electronics
NEXT STEPS
  • Research the specifications and applications of high power resistors
  • Learn about resistor power ratings and their impact on circuit design
  • Explore heat management techniques in high power electronics
  • Examine the differences between various resistor types and their uses
USEFUL FOR

Electronics enthusiasts, beginners in circuit design, and anyone involved in selecting or using high power resistors in their projects.

Undacuva
Messages
8
Reaction score
0
Hi,
I'm looking for a high power resistor. I just got confused over some nomenclature I haven't seen before. (Yes I'm a beginner). I'm seeing resistors named like this: "3R9ohm"and "4R7ohm" I know what R is in V=IR. But in the rating of a resistor? Can someone help?
 
Engineering news on Phys.org
Power rating (in Watts) is a totally different thing to the resistance of a resistor

your 3R9 and 4R7 are the resistive values ie. 3.9 and 4.7 Ohms respectively

resistors can be purchased with all sorts of power ratings from ~ 1/8 Watt to 100's of Watts
for every day electronics ( maybe higher wattage ratings in high voltage/current situations )Dave
 
  • Like
Likes   Reactions: 1 person
The power rating is all about getting rid of heat, so transistors rated for a high power are typically quite large. If you do not know what resistance values mean, I'm not sure if you really need a high power resistor. What is the purpose of the resistor?
 

Similar threads

Will the bleed resistors enable a shorter path to ground or not?
  • · Replies 80 ·
3
Replies
80
Views
5K
Couple Questions about this Resistor Datasheet
  • · Replies 4 ·
Replies
4
Views
2K
Introductory Circuit Analysis—power ratings
  • · Replies 6 ·
Replies
6
Views
2K
Power Over Fiber for Small Sensors
  • · Replies 20 ·
Replies
20
Views
2K
Active power dissipated by a resistor from DC to RF
  • · Replies 5 ·
Replies
5
Views
2K
I'm trying to intuit how pull-up and pull-down resistors work
  • · Replies 33 ·
2
Replies
33
Views
5K
Power supplied by AC component + DC component = total power?
  • · Replies 6 ·
Replies
6
Views
4K
Keep setting fire to discharge load resistor - Wattage limit
  • · Replies 20 ·
Replies
20
Views
3K
Can a different Ohm rating resistor burn a pc motherboard?
  • · Replies 15 ·
Replies
15
Views
5K
Understanding Reactive Power Measurements with a Smart Meter
  • · Replies 4 ·
Replies
4
Views
3K