# What does it mean that a resistor has value of 56E?

I found on one schematic that has resistor with value 56E.

I don't know what does that mean.

Can you give me some information, please.

I know it's old topic, but I just saw it since I had the same question. Anyway, here's the background story behind "E" letter.

The usage of the Latin letter E instead of R is not standardized in IEC 60062, but nevertheless sometimes seen in practice. It stems from the fact, that R is used in symbolic names for resistors as well, and it is also used in a similar fashion but with incompatible meaning in other part marking codes. It may therefore cause confusion in some contexts. Visually, the letter E loosely resembles a small Greek letter omega (ω) turned sideways. Historically (f.e. in pre-WWII documents), before ohms were denoted using the uppercase Greek omega (Ω), a small omega (ω) was sometimes used for this purpose as well, as in 56ω for 56 Ω. However, the letter E is conflictive with the similar looking but incompatible E notation in engineering, and it may therefore cause considerable confusion as well.

https://en.wikipedia.org/wiki/Resistor#Electronic_symbols_and_notation

E is a placeholder for the decimal point. This is commonly denoted by R as well. Some examples to make it clearer:

$$5E6 = 5R6 = 5.6\Omega$$ $$56E = 56R = 56\Omega$$ $$560E = 560R = 560\Omega$$

The reason that these letters are used in place of a decimal point is to make the values easier to read. If you had a schematic with a 2.2 ohm resistor and 2.2 was printed on the page, it could easily be mistaken as 22 ohm. The decimal placeholder reduces the likelihood of an error.

When it comes to values greater than 1k ohm, you won't normally see E or R used but rather the usual SI multipliers (k, M, G etc). Some examples:

$$1k = 1k\Omega$$ $$2k2 = 2.2k\Omega$$ $$5M6 = 5.6 M\Omega$$

• Thank you very much. So what does "E" mean ? – mitesh gandhi Aug 10 '16 at 7:37
• E doesn't mean anything particular. It is just a convention. E and R are used as decimal place holders to make values easier to read correctly. I modified my answer to include this. – bitshift Aug 10 '16 at 7:38
• I'm sure you are correct but how confusing. If I saw 6E8 I would naturally assume it meant 6 x 10$^8$. Then there's the confusion with the E series of resistors and the usage of E for voltage. Nothing wrong with "R" as the decimal point but E sounds really wrong to me. – Andy aka Aug 10 '16 at 7:56
• @Andyaka It is definitely not as common as using R but does exist in that form. There was a question asking about "R" a while ago and we discussed the usage of "E" as well. See here electronics.stackexchange.com/questions/246920/… – bitshift Aug 10 '16 at 7:58
• It is actually the symbol for the nomadic tribes in the southwest of Ethiopia – bitshift Aug 10 '16 at 9:49