Is this a resistor? Help me identify please.

  • Thread starter Thread starter n00bsauce
  • Start date Start date
  • Tags Tags
    Resistor
Click For Summary

Discussion Overview

The discussion revolves around identifying a component suspected to be a resistor found in a damaged power supply. Participants explore the color coding of the resistor's bands, particularly the presence of silver as a third band, which raises questions about its validity. The conversation includes attempts to determine the resistor's value and wattage based on its appearance and context within the circuit.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant identifies the color bands as Brown, Blue, Silver, Gold, Black and expresses confusion over the silver band, suggesting it might be interpreted as gray for calculation purposes.
  • Another participant estimates the wattage of the resistor to be between 0.25W to 0.5W, asserting confidence that it is a resistor.
  • A different participant provides a link to a resource for 4-band resistors, questioning whether the resistor is part of a feedback loop in the power supply.
  • One participant notes that the color of the bands can change due to oxidation, complicating identification.
  • Another suggests that the resistor may not follow the standard 5-band scheme and proposes it could be using a 4-band scheme, leading to a calculated value of 0.16 ohms at 5% tolerance.
  • One participant emphasizes the unusual nature of a silver band as the third color and suggests it should be read as gray, while another counters that silver could be common in specific applications.
  • There is a suggestion to measure a similar resistor in the circuit if it is a dual-type power supply, which could help confirm the value.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of the color bands, particularly the validity of silver as a third band. There is no consensus on the resistor's exact value or function within the circuit, and multiple competing interpretations remain.

Contextual Notes

Participants acknowledge that the condition of the resistor may have altered its appearance, and there are unresolved assumptions regarding its function and placement within the circuit.

n00bsauce
Messages
8
Reaction score
0
I need some help identifying what I'm pretty sure is a resistor. I have a power supply that blew up, I opened it up and everything looks ok except for this.

resistor-2.jpg

resistor.jpg


The color bands are:
Brown
Blue
Silver
Gold
Black

The only problem is that silver isn't a valid color for the third band. I know gray is, but it definitely looks silver to me. What else could it be?

If I use gray for the third band I get a 16.8 ohm 20% resistor, what wattage do you suppose it could be using the penny for scale?

Thanks for any help you can offer.
 
Engineering news on Phys.org
Most likely .25W to .5W. I am pretty sure that it is not any higher than .5W.

I am also pretty sure that it is a resistor.
 
Try this:

http://www.dannyg.com/examples/res2/resistor.htm

This site gives 0.16 ohms +/- 5%. Is this a series or shunt resistor in the power supply? Is it part of a feedback loop? Perhaps knowing the function of the resistor will help determine its value.

Bob S
 
Your link is for a 4 band resistor, mine is a 5 band. And I still can't figure out why the third band is silver, which isn't a valid color.

http://hirophysics.com/Labsheet/resis-codes/5-band.jpg

I'm not sure what the function is, the resistor wasn't very easy to get at, as there's a lot of stuff on top of there it was and I had to use a soldering gun on the back of the board and tweezers to pull it out. I figured if I could figure out what to replace it with I would just solder it to the back of the board and not have to do major disassembly.
 
Last edited by a moderator:
Other than silver, you have to guess at the other colors. The paint oxidizes and changes color. They always look like black and brown after a good cooking.
 
Yes reading burnt resistor colors is always a pain_ITA.

It looks like it doesn't follow the standard for a 5 band resistor. This leads me to believe that it may actually be using the 4 band scheme (with the final black band as an unknown function).

This would make it a 0.16 ohms at 5% tolerance.

Where abouts in the circuit was it located n00b? Was it in series with the output (typically a low valued resistor like this is used here as part of the current limit circuit btw), if so then 0.16 ohms is certainly feasible. What is the rated output current of the unit?
 
My friend,

first you need to accept the fact that the condition of any resistor upon burning would be ... !

Hence, if you are guessing it to be a silver, you need to realize what it might be like before.


Anyway, silver is a very much unusual colour as a third band. Perhaps you should consider reading it as grey !

Hope for best !
 
Ali Inam said:
Anyway, silver is a very much unusual colour as a third band!

Unusual is very much a relative term. If for example this resistor is in series with the power supply output then silver (sub one ohm) would be a very common multiplier for a resistor in that particular application.

BTW. Forgot to mention this before n00b, but if this is a dual type supply then you might well find that the resistor has a "mate" of the same type and value in the other channel.
 
uart said:
Unusual is very much a relative term. If for example this resistor is in series with the power supply output then silver (sub one ohm) would be a very common multiplier for a resistor in that particular application.

BTW. Forgot to mention this before n00b, but if this is a dual type supply then you might well find that the resistor has a "mate" of the same type and value in the other channel.

You're right! I didn't even think of that, I can just measure the other one.
 

Similar threads

  • · Replies 33 ·
2
Replies
33
Views
6K
  • · Replies 24 ·
Replies
24
Views
9K
  • · Replies 33 ·
2
Replies
33
Views
4K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 31 ·
2
Replies
31
Views
13K
Replies
78
Views
10K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 10 ·
Replies
10
Views
4K