need resistor 0.3ohm 0.2% 2W

Discussion in 'The Projects Forum' started by smilem, Sep 4, 2010.

  1. smilem

    Thread Starter Active Member

    Jul 23, 2008
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    Hi, I'm looking for a resistor to replace in place of blown one used in analog multimeter.

    resistor 0.3ohm 0.2% 2W

    Please see attached schematic and excerpt from parts list.
    Seems Russians used to make such a high quality parts that I'm unable to find replacements even now ?
     
  2. marshallf3

    Well-Known Member

    Jul 26, 2010
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  3. smilem

    Thread Starter Active Member

    Jul 23, 2008
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  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    Why not get some nichrome wire and make one yourself? .3 ohms would be a quite small one(physically)
     
  5. Ghar

    Active Member

    Mar 8, 2010
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    240V across a 0.3 ohm resistor is 800A.
    It won't ever have 240V across it, but if you're still worried go with the Vishay one which says 500 Vrms for dielectric withstand.
     
  6. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    That type of R is definitely nichrome wound ones.
    I doubt that original has that tolerance to begin with.
     
  7. marshallf3

    Well-Known Member

    Jul 26, 2010
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    I'd go with the higher voltage one so long as it will physically fit, however as it seems to be asociated with the 3A scale it's not going to be seeing 800A by any means.
     
  8. smilem

    Thread Starter Active Member

    Jul 23, 2008
    132
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    Thanks everyone for your help.

    I'll go with RS02BR3000FB12 vishay-dale, 3 Watts, 0.3 Ohms, 1 %

    Since I have digital meeter accuracy wise it doesn't need to be super, precise. However it is still handy to measure using analog too, especially since it not made in china crap type multimeter :)

    I should also include a 3A fuse I think, to protect it next time it would not blow if by accident I measure stronger current.

    Can anyone recommend self restoring fuse for this task, forgot how they are called? Or can I use simple glass fuse?
     
  9. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Fast blowing glass fuse is a lot faster and will catch things better than others. They do make poly fuses that reset themselves but they're not that fast and they also introduce a lot more resistance into the circuit than a simple 1A glass one would.
     
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