Electronic – What does it mean that a resistor has value of 56E

power electronics

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.

Best Answer

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.


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