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What does the "E" signify in a resistor value e.g. 470E — Parallax Forums

What does the "E" signify in a resistor value e.g. 470E

Ron CzapalaRon Czapala Posts: 2,418
edited 2015-05-08 07:10 in General Discussion
I was looking into CD4027 circuit schematics and saw a resistor specified as "470E"

http://www.electronicshub.org/jk-flip-flop-using-cd4027/

What does the "E" mean? Tolerance?

Thanks,
Ron

Comments

  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2015-05-05 10:17
    I've seen it a few times and thought initially it was incidental font substitution from the Greek Omega symbol. (In Windows, the usual substitution is to the letter W, because of the way the Symbol font maps to the ASCII character set.) But it occurs often enough that I gather it's an alternative for R, as in 4E7 or 4R7 meaning to us Yanks 4.7k ohm. The E might pertain to the "E-series" of standard resistor values.
  • ercoerco Posts: 20,256
    edited 2015-05-05 11:14
    GordonMcComb wrote: »
    The E might pertain to the "E-series" of standard resistor values.

    Very interesting, I Googled this: http://www.resistorguide.com/resistor-values/

    E6, E12, E24, etc...
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2015-05-05 11:16
    Maybe 470E is hexadecimal. :) Or perhaps the schematic was drawn in Basque country. Where we would use the suffix "R" for resistance, in Basque it's erresistentzia, so they would naturally use an "E." Or ... I just don't have a clue.

    -Phil
  • Ding-BattyDing-Batty Posts: 302
    edited 2015-05-05 11:22
    According to what I read, it looks like the "E" fulfills the same purpose as the "R" in 470R == 470E, 0E22 == 0R22 (for 0.22 Ohm resistor). Resistors on AliExpress are sometimes listed with both values. It is not a tolerance value, because "E" is not one of the tolerance letters in use.
  • davejamesdavejames Posts: 4,047
    edited 2015-05-05 11:26
    erco wrote: »
    ... I Googled this: http://www.resistorguide.com/resistor-values/

    Thanks for that, Erco.

    Somehow, over the many years involved with things elektronik, I either never took the time to research the "E". Now I know why 1% metal film resistors are segregated as they are.

    I learned something today. :thumb:
  • Ron CzapalaRon Czapala Posts: 2,418
    edited 2015-05-05 11:29
    erco wrote: »
    Very interesting, I Googled this: http://www.resistorguide.com/resistor-values/

    E6, E12, E24, etc...

    I found that site as well but it really didn't spell it out. If it was E12 I would have expected it to say 470 E12 rather than just 470E.

    Still haven't found an exact description/explanation...
  • idbruceidbruce Posts: 6,197
    edited 2015-05-05 11:29
    E = Enot = Ohms or that is what the web says
  • Ron CzapalaRon Czapala Posts: 2,418
    edited 2015-05-05 11:35
    enot huh?

    Similar discussions here http://groupdiy.com/index.php?topic=32129.0

    and

    http://www.edaboard.com/printthread67699.html
  • idbruceidbruce Posts: 6,197
    edited 2015-05-05 11:41
    Ron

    Yes, Enot, but I read that it is more specifically used for Iskra brand resistors
  • Mark_TMark_T Posts: 1,981
    edited 2015-05-07 07:31
    The E key is next to the R key on the qwerty kbd...
  • kwinnkwinn Posts: 8,697
    edited 2015-05-07 09:03
    Mark_T wrote: »
    The E key is next to the R key on the qwerty kbd...

    So you think it may be a typing error?
  • Mark_TMark_T Posts: 1,981
    edited 2015-05-08 07:10
    kwinn wrote: »
    So you think it may be a typing error?

    Well there are at least two other mistakes(*) in that circuit, I wouldn't be surprised.

    (*)No decoupling, push-switch crowbars the supply
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