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Type of resistor, and where can I salvage one?

Discussion in 'General Electronics Chat' started by halleffector, Oct 21, 2016.

  1. halleffector

    halleffector Member

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    What type of resistor is this? Carbon? I see at least it is 0.22 ohm.

    Where can I salvage an equivalent resistor? This was for the power supply circuit for an LCD.

    How much difference in ohm can I get away with?


    [​IMG]
     
    Last edited: Oct 21, 2016
  2. cowboybob

    cowboybob Well-Known Member Most Helpful Member

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    Your image file didn't load.
    That small a value, from my experience, will be hard to find by salvaging a component. You'd also need to know its wattage rating.
    No way to know without a schematic of the circuit it is (or was) in when it failed - if that's what happened.
     
  3. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    Metal film.

    I do not know where (how) it was used. Probably current sensing.
    .20---.22----.24 Probably could more over one value but not more. Really a big guess.
    Something may have failed that caused the resistor to go. So replacing the resistor might not do anything but kill the second resistor. More likely a transistor that first popped and caused too much current.
     
  4. dave

    Dave New Member

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  5. halleffector

    halleffector Member

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    Fixed the image, sorry about that.
     
  6. cowboybob

    cowboybob Well-Known Member Most Helpful Member

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    looks like a 1/2W, Maybe 1W. If you can find 4, 1Ω resistors and put them all in parallel (giving you 0.25Ω, if your lucky...), that might work. Again, and as ron notes, not knowing for sure its purpose, it's just a guess.
     
  7. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    Where......in a power supply for an LCD. LOL Might find one in a power supply for a TV/CRT monitor, computer power supply.......
     
  8. halleffector

    halleffector Member

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  9. halleffector

    halleffector Member

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  10. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    My guess is a 0.22 Metal Oxide resistor, http://www.digikey.com/product-sear...t=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25 on the order of 1 W.

    Check dimensions.

    Metal oxide resistors are typically used as safety resistors because they usually vaporize. Metal film resistors tend to puddle. If it's wire wound resistor, you should be able to tell. The other types are carbon film and carbon composition.

    Each has an intended use and carbon composition is the lowest cost.
     
  11. halleffector

    halleffector Member

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    Thanks.

    But what happens if I use a 5W resistor and it should have been 1W? As long as the resistance is the same, wouldn't it be fine if it has a higher rating?
     
  12. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    In most cases yes. Low value resistors are either used as current sense resistors or basically used as a fuse. Sometimes resistors that are supposed to get hot, so to speak are mounted on ceramic standoffs to get them above the board.

    A metal-oxide resistor will literally break in two pieces if overloaded. Note that these resistors are call "Flame Proof" for that reason.

    it is hard for me to tell just what kind of resistor it was. The orange one (other thread) on your board shows more of the metal oxide characteristics.
     
  13. dr pepper

    dr pepper Well-Known Member

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    A .22 in a monitor is likely to be a current sense as mentioned, and also likely to be in a smps, for that reason an inductive resistor such as a wirewound probably wont be suitable.
    Paralleling carbons might work however looking at the way the old one has failed I'd say its a fusible, paralelling carbons might be a way of proving that is the case and nothing else is wrong, however you wont have the protection that a fusible provides.

    You also should check the switching transistors, rectifiers and caps to make sure there are no shorts, something like this probably blew that thing in the first place.
     

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