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Resistor codes

Discussion in 'General Electronics Discussion' started by SparkyCal, Jul 19, 2020.

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  1. SparkyCal

    SparkyCal

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    Mar 11, 2020
    I understand how to decipher resistor codes online or through a chart, but how do you know which end is the first color? In other words, how can you identify color band 1 as opposed to color band 5?

    Thank-you
     
  2. bertus

    bertus Moderator

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  3. Martaine2005

    Martaine2005

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    May 12, 2015
    That question really tickles me. I asked the same question.
    I still have problems sometimes. I found it easier to work out both ways and see what was more in line with current values. Then measure it.
    Or measure first then calculate both ways. It does get easier for more often used values.
    Have a resistor colour code calculator open on your desktop so you can quickly input the colours. I did that too.
    Print out the different E series for quick reference. That helps too. Mine are laminated.

    Martin
     
  4. bertus

    bertus Moderator

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  5. SparkyCal

    SparkyCal

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    Mar 11, 2020
    Great guide. Thank-you. My problem however is how to physically determine which side of the resistor is left and which is right. This is an important distinction when reading color bands. So, I am wondering, how do I know what the left side of the resistor is, so that I can look up the colors in the proper order?
     
  6. bertus

    bertus Moderator

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    Nov 8, 2019
    Hello,

    Did you see this picture on the page I in the thread I linked to:

    resistor color code.png

    Bertus
     
  7. SparkyCal

    SparkyCal

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    Mar 11, 2020
    I did but if I cant tell which side of the resistor to read from, how would I know. For example, if I have one that is

    brown. Black black red red

    how do I know whether brown is the first colour or red?
     
  8. bertus

    bertus Moderator

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    Nov 8, 2019
    Hello,

    I would say that that resistor is 10k 2%.
    Often the tolerance band is wider as the rest, or the distance between the tolerance band and the rest is wider.

    Bertus
     
  9. davenn

    davenn Moderator

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    Sep 5, 2009
    You are still missing the point of the OP's valid and yet unanswered Q



    That was what should have been in your first response :) :) :)
     
  10. davenn

    davenn Moderator

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    Sep 5, 2009

    It's, as Bertus finally got to, all about distance between the tolerance band and the value bands

    On 4 band resistors, this is easy as the tolerance band is well separated from the 3 value bands

    A little more difficult on a 5 band resistor, like a metal film type, but there are still enough of a gap if you look carefully
    Also a big giveaway is that most of the tolerance or temp coefficient colours do NOT get used for first digit value colours
    eg. silver, gold
     
  11. SparkyCal

    SparkyCal

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    Mar 11, 2020
    Thank-you folks. I think you have answered it.
     
  12. SparkyCal

    SparkyCal

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    Mar 11, 2020
    By the way, I think i was having problems because on the 5 band resistors, it is very difficult to see the spaces between bands. I will print out that chart for quick reference, as well.
     
  13. Martaine2005

    Martaine2005

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    May 12, 2015
    1% and 2% can be a real PITA.
    Like I said previously, I have to read them both ways to find the logical Value. Then measure to verify.

    I made myself laugh when reading a 100Ω 1%.

    Martin
     
  14. bertus

    bertus Moderator

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    Nov 8, 2019
    Hello,

    As @Martaine2005 said, have a list of possible values ready.
    The 220 Ohms does not exist in E48 , E96 and E192.
    See the attached PDF for the values.

    Bertus
     

    Attached Files:

  15. SparkyCal

    SparkyCal

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    Mar 11, 2020
    I should mention that when i responded and provided resister colors, I was not at home and I was simply making the colors up. It wasn't a real resistor. i was just using it as an example.
     
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