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1% colour codes

Discussion in 'Electronic Design' started by Terry Pinnell, Nov 25, 2004.

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  1. In all the years in this hobby, I suppose this is the first time I've
    had to look closely at resistor colour codes. My latest parts order
    included a few .125W 1% resistors. With glasses removed and peering
    closely I see
    10k: brown, black, black, red, brown
    100k: brown, black, black, orange, brown

    I'd instinctively looked for a splash of orange and yellow
    respectively. Removed from their tape and mixed with my other stocks,
    interpretation hardly seems intuitive. Deciding from which *end* to
    read is hardly obvious for starters!
     
  2. Yes, those crappy 4-band colour codes. They came in a
    few years ago, not exactly easy to read. I'm afraid
    you always have to have your DMM handy from now on Terry.
     
  3. Leon Heller

    Leon Heller Guest

    I've used 1% metal film resistors for years. I write the value on the tape,
    and do the same with SM Rs and Cs. The brown ring (tolerance) should be
    separated from the others.

    Leon
     
  4. Robert Baer

    Robert Baer Guest

    Since one has one percent resistors, that means an *extra* significant
    digit for the value.
    So: 10K = 100*10^2 ohms @1% and 100K = 100*10^3 ohms @1% (note the
    colors follow this).
    As far as which end to start from, if both ends are "1" (brown), then
    there can be a problem.
     
  5. Most of my dabbling now uses breadboard, so I'll return a newly-used
    (and shaped) resistor to the container, not the tape. The ideal would
    be more containers of course, but not practical here.
    I'll take a look later. Pretty darned hard to see anyway.
     
  6. Thanks, understand that. But my point is that it's poorly chosen
    coding, because it's inconsistent with the 4-band system. I want
    yellow to mean '100k-999k', etc.
    As in this example. And I guess for most of my 1% resistors, which
    tend to be 100, 1k, 10k, etc.
     
  7. You could still get 1% in the 3 band codes, last time I looked... you
    just had to choose the right manufacturer (rohm?).

    All my new resistor purchases are surface mount now, so the problem
    does not arise. (Except you need a magnifier to read them of course).
     
  8. Paul Burke

    Paul Burke Guest

    Not so much the tolerance as the series. Once you get to E96, you need
    the extra band for weirdy values like 15k4. I only use 1% these days, as
    it saves stocking multiple ranges. Except of course where it's necessary
    to use 0.1% or whatever.

    Paul Burke
     
  9. Hi Terry
    http://www.safepub.com/Catalog/General/eyemagn.htm#galilean system
    or google for binocular loupes
    The medical ones are EXPENSIVE!

    (I need a pair)



    martin

    Serious error.
    All shortcuts have disappeared.
    Screen. Mind. Both are blank.
     
  10. Wow - 136USD! I'll struggle on a bit longer and spend the 73UKP on
    Chablis instead <g>.

    Actually, although I'm very shortsighted, anything under about 6"
    (15cm) away is sharp without my glasses. Groping for them again after
    a spot of close-up soldering can be hazardous though!
     
  11. I'm sure I read somewhere that one end band is supposed to be wider than the others to indicate
    which way round - I think it's the tolerance band.
     
  12. Pooh Bear

    Pooh Bear Guest

    The extra digit makes those bands red and orange respectively.
    The tolerance band should be separated from the value by a larger
    distance.


    Graham
     
  13. Pooh Bear

    Pooh Bear Guest

    I find this kind of thing quite useful.

    http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=272527&N=401

    Keep a 5x and 7x handy.

    Graham
     
  14. I was at an electronics show a few years ago where a vendor of really small
    surface mount parts was giving away 3x magnifiers. I also purchased a pair
    of magnifier reading glasses at Walmart. The combination is good enough to
    convince me that I don't want to try soldering those little beasties. Me
    finger tremor is about two-three pins worth on the tightest-pitch ICs we
    use.
     
  15. Jim Thompson

    Jim Thompson Guest

    [snip]
    You're not drinking enough ;-)

    ...Jim Thompson
     
  16. Rich Grise

    Rich Grise Guest

    Ya took tha wordsh right outta my *hic* glash.

    %-*
    rCHI
     
  17. Will that a) increase the tremor, b) decrease the tremor, or c) make me not
    care about it.
     
  18. how about RedBull and vodka?
    It keeps the yooth of today partying all night, vodka to calm the
    nerves, and caffine for the reciprocal


    martin

    Serious error.
    All shortcuts have disappeared.
    Screen. Mind. Both are blank.
     
  19. Paul Burke

    Paul Burke Guest

    They party all night because they are yoof, despite what they consume.
    Just like we used to do on cheap cider and Party 7s, remember?
     
  20. Terry Given

    Terry Given Guest

    Recently I have been using smt resistors with codes on them - how the
    hell do you figure "768" = 604 ohms, or "010" = 100k.

    I made a clip up with some copper pipe hammered to form tweezers, and a
    plastic clothespeg, and attached leads & banana plugs to it so I can
    easily measure 0603 Rs and Cs.

    OTOH film cannisters are great smt component holders.

    Cheers
    Terry
     
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