# E series

Discussion in 'General Electronics Discussion' started by dcac, Apr 20, 2015.

1. ### dcac

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Jul 10, 2013
Hi

does anyone know where is the magic behind the E series rounding?
Some number correspond to Renard/geometric series other rounded up others are rounded down?

for example 10^(6/12)=3.1623 in E12 this number corresponds to 3.3. Does anyone know how the rounding works?

2. ### Harald KappModeratorModerator

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Nov 17, 2011
Your reference to Renard series is a near hit. Read more here. The magic is in the tolerances such that within one series no gaps exist between adjacent numbers including the tolerances.

3. ### dcac

56
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Jul 10, 2013
I guess the only way is to memorise the numbers because there are no easy way to calculate because of this tolerance they must to obey.

4. ### davennModerator

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Sep 5, 2009

1, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2

and times 10 for each step up the scale

10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82

etc

Dave

5. ### BobK

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Jan 5, 2010
Well, that is the E12 series, what about E96?

Bob

6. ### davennModerator

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Sep 5, 2009
he was only asking about the E12 which is the common one

Even I have never bothered memorising any of the other series ... not worth the effort

7. ### dcac

56
1
Jul 10, 2013
Yeah not worth, but my lecturer wants me to know, kinda annoying in the way

Last edited: Apr 23, 2015
8. ### davennModerator

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Sep 5, 2009
well I gave you the E12 range as I said ... pretty easy to memorise
have fun

1,114
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Aug 13, 2011
I almost have a complete E24 series at work and I almost have it memorized.

10. ### davennModerator

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1,909
Sep 5, 2009

ohhh that take a little more effort