What kind of resistor is this?

Discussion in 'General Electronics Chat' started by pand0ra, Oct 17, 2011.

  1. pand0ra

    Thread Starter New Member

    Oct 17, 2011
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    I'm trying to swap out resistors and am not entirely sure if it is a 0.2 Ohm resistor and need someone to verify for me (I think it's Red, Black, Silver, gold). Also, where is a good place to pick up a replacement? Digikey?
     
  2. Wendy

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    Mar 24, 2008
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    It isn't, it is a PCB fuse, 2A.
     
  3. pand0ra

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    Oct 17, 2011
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    Sorry, I should have marked the picture. There are 2 of them with the color bands. I think both are burned out.
     
  4. Wendy

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    You could ohm them with a meter. While they could be burned out, I doubt they are. They are indeed well baked, but a lot of resistors that get hot look like that over time.

    I am betting they are 10Ω. From their size I'm thinking either ½W or 1W, and gold is 5% tolerance.
     
  5. SgtWookie

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    Jul 17, 2007
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    I can't really tell.
    Red-blk-silver-gold would be 0.2.
    Brn-blk-silver-gold would be 0.1.
    Brn-blk-blk-gold would be 10, but that 3rd band really doesn't look the same as the black band - to me, anyway.
     
  6. Wendy

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    An ohm meter, as I suggested, would eliminate a lot of possibilities.
     
  7. pand0ra

    Thread Starter New Member

    Oct 17, 2011
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    I've tried a meter (not sure if I'm using it correctly) but it returns nothing. I can get a value from other resistors though.
     
  8. SgtWookie

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    OK, so what is the voltage across the resistors when the circuit is powered?
    That will help to decide what resistance should be there.

    Looking again at the picture; it could very well be two black bands, as it looks like the center of the resistor (where the gray-looking band is) got a lot hotter than where the definitely-black band is.
     
  9. BMorse

    Senior Member

    Sep 26, 2009
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    looks like Red, Black, Brown to me with a gold band, 1/2 watt
    Digikey would be one good source.....

    Is that part of a telephone circuit??
     
  10. Wendy

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    That looks like <brown> <black> < maybe black> space <gold> to me, just like the quarter watt off to the side looks <brown> <black> <green> <gold>.

    With an ohm meter and no power to the circuit you should get some reading.
     
  11. SgtWookie

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    Our OP has already said that they can measure other resistors, but they get no reading across those two (I'm assuming they read infinite Ohms instead of 0 Ohms)
     
  12. Wendy

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    Perhaps, but it is rare condition. Most times I've ever seen open I've also seen a crack in the resistor. Those look intact. I've had them drift to ridiculous values, but rarely open all the way without physical damage.

    I suspect the OP is going to need a schematic or another similar unit. If the similar unit is of the same age I would also bet the resistors look the same.
     
  13. pand0ra

    Thread Starter New Member

    Oct 17, 2011
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    I'm trying to repair a electric blanket controller.
     
  14. pand0ra

    Thread Starter New Member

    Oct 17, 2011
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    They look a little burnt in the middle to me so that's why I was guessing they are damaged.
     
  15. Wendy

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    I've seen that look in perfectly OK resistors. I didn't like it, but that is why you need to be sure they are ohmed out. If you have ohmed them correctly and they are open, then that is your problem. However, it is rare, which is why I suggest you do it again to verify they are open. Assumptions are a major pain, and can come back to bite you.
     
  16. pand0ra

    Thread Starter New Member

    Oct 17, 2011
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    Will do. I'll take another test of them when I get home tonight. Thanks for the feedback everyone!
     
  17. pand0ra

    Thread Starter New Member

    Oct 17, 2011
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    So, if I set the multimeter to 2kΩ the result I get is ~.491 for both. I think I had it set to volts the first time but didn't notice.
     
  18. Adjuster

    Well-Known Member

    Dec 26, 2010
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    0.491 on 2kΩ f.s. =491Ω? Identical results to 3 figures from a pair of visibly cooked resistors sounds a bit odd.

    Perhaps they are a couple of 1kΩ in parallel, in which case they would be close to nominal values, despite a red band baking to grey.

    Of course, it may just be coincidence, really they may be open and other parts may determine the reading.
     
  19. Lundwall_Paul

    Member

    Oct 18, 2011
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    When measureing on the PCB and if it is a .2 ohm your reading should not be any higher then .2 ohms
     
  20. pand0ra

    Thread Starter New Member

    Oct 17, 2011
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    I'm still learning about this stuff, so should I swap those out? Should they work since they aren't registering at .2 ohms?
     
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