Red,red, silver, gold black resistor?

Discussion in 'General Electronics Chat' started by uriahsky, Aug 7, 2012.

  1. uriahsky

    Thread Starter Active Member

    Apr 27, 2009
    42
    2
    I can't believe I am asking this question. I thought by now this was all standarized, unless I am missing the obvious. I tried three different calculators and they all got confused.
    Red,red,silver,gold black, what exactly is this?
    Thanks
    Russ
     
  2. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    red red silver gold black
    2 2 divide by 100 5% I don't know
    likely .22 ohms 5%

    red red grey gold black
    2 2 8 divide by 100 0%
    Not likely/ 2.28 ohms 0%

    Can you measure the resistance?
     
  3. uriahsky

    Thread Starter Active Member

    Apr 27, 2009
    42
    2
    It is measuring 39 ohms, and we know it has to be some form of 22, so 39 is too high. Perhaps it is 22 ohms? I think this is the current sense resistor in this power suply I am working on.
    Thanks
    Russ
     
  4. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    39 ohm reading suggests it is ruined.
    It is also important to get it right. If this is the sense resistor on a switching supply and you get it wrong, the smoke could start in microseconds.

    Time for research!
     
  5. BSomer

    Member

    Dec 28, 2011
    433
    106
    Are you measuring that "in-circuit"?
     
  6. uriahsky

    Thread Starter Active Member

    Apr 27, 2009
    42
    2
    I removed and it still measures 39 ohms. I contacted the manufacture but they haven't responded with the schematics. It is a Weihai HTD180240-T1
     
  7. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    The black stripe indicates a temperature coefficient of 250ppm/°K.
     
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