06-14-2016, 02:16 PM (This post was last modified: 06-14-2016 02:18 PM by Claudio L..)
Post: #296
 Claudio L. Senior Member Posts: 1,885 Joined: Dec 2013
(06-14-2016 12:48 PM)Vtile Wrote:
(06-13-2016 07:59 PM)emece67 Wrote:  I suppose you are referring to the later use, with the prefix replacing the decimal dot/comma. I have no idea if it is standardized by anybody, but it is in common use in EE. See, for example, the schematics on this service manual of a Nokia phone. You will see lots of components whose value is something like 3k3, 4u7 (4.7·10^-6), 1u5, 2u2, 6p8 (6.8·10^-12) and so on.

I suspect that this is as a safeguard against tiny dots "missed" in big paper sheets.

Regards.
It also shortens the notation by one character. I don't know If I have seen it anywhere else than electronics and with resistor values. With magnitude prefixes you need to know the value of such prefix and with so called engineering notation (with magnitude steps of thousand) you need to know the correct prefix for a value.

While 3k3 style marking would be cool, I don't see much of an true value for it. Since anyone who uses such should be fluent of magnitude prefixes anyway, so 3.3k(Ohm) or 3.3e3 should be as clear as 3k3..

Interesting that they use this notation to omit actual physical units. 3k3 = 3.3_kΩ and 100p = 100_pF. But do they use this notation to actually perform calculations?
Let's say your result from a calculation is 3243.54534_Ω (or just the number, forget the unit). I don't see an easy way to display it, it would look like 3k24354534 ? or 3.24354534k?
The first one looks like an integer at first sight, as the letter gets lost in the numbers so while it might work for display of final numbers (like resistor values, all rounded and neat), it's not very good for general number display. The second form is doable (it's relatively simple to replace the ENG exponents for a single letter).
There's a lot of room for confusion, though, as 100k looks very similar to 100_K, same thing for 100m and 100_m. There's also the issue of which prefixes to use (all 20?). If I read 100a on the screen, I don't personally know what that means, unless I go to an SI reference table to see that a = atto = 10^-18.
There's also a prefix E = exa = 10^18, which looks like I forgot to print the exponent:
100E and 100E3 are quite similar.

If there's enough interest or a real use I can implement it, but I see some potential issues with this notation.

EDIT: I just thought of parsing issues if the user types 100E, is that a syntax error or the user actually means 100*10^18?
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